For clothing, something like what Lee's describing is actually the last thing you'd want. What your daughter will want to do is approach the concept not as "making latex", but as a problem of light and shadow. For just a flat swatch of fabric, the light and shadow would be completely different than they would be on a full garment.
You won't find any automatic solution for this. It's gonna take good old fashioned artistry. There's no way around that (nor should there be).
To start, take a look at a real latex outfit, like the one in this photo:

There are three basic things to pay attention to, the behavior of the material as a solid object in 3D space, its reflective properties, and how its highlights and shadows define it as wrapping around a human body.
Here's a brief introduction to each of the factors, and a bit of advice on how to paint similar effects by hand in Photoshop:
1. Behavior of the Material
The first key to replicating the appearance of various materials in texturing (and in artwork in general) is to pay attention to how the material behaves when draped on particular objects. For clothing textures, that means how it behaves when draped over a humanoid figure.
Notice how the top hugs the body tightly around the shoulders, breasts, and hips, but wrinkles just slightly around the waist and armpits, where the material ends up compressed. Notice on the pants, there's a similar pattern. It's very tight around the hips, buttocks (which are not seen in the picture), and thighs, and it bunches up and wrinkles around the knees, and the lower pelvis. Since latex is not as elastic as skin, the material ends up wrinkled in places where the body bends, or where there's an inner curve. It ends up stretched tight in areas where there's an outer curve.
So, the first thing to mark on your clothing template, is where the wrinkles go. We'll get to how to paint them realistically later on, but for now, just draw some lines.
2. Reflective PropertiesEverything in the previous section would apply equally to any material with similar thickness, rigidity, and elasticity to latex, and there are many materials that fit that description. So what makes this particular material scream "I'm latex"? Afterall, the photograph itself is just a collection of pixels, just like your texture will be, and nothing at all like actual latex.
As with all material surfaces, what defines latex visually to us as human beings is the particular way light reflects off of it. Latex is generally very shiny, but not particularly reflective. In other words, it has high contrast between the highlights and the shadows, and not much transition in between them. Notice in the picture, you can see a lot of white highlights on the black material, but you don't see a whole lot of gradation between the black and the white. The shine is almost all or nothing.
For creating that kind of effect in Photoshop, you'll find that the dodge tool is your friend. Its job is to paint highlights, and that's exactly what all that shine is, highlights.
Before we get into the dodge tool itself, it's important to note that it's not a real good idea to start with black as the color for your garment. Even though black may be what you'll want at the end, starting with black will make the dodge tool unable to function. Start with a dark gray instead. We can always use the burn tool later to darken the midtones and shadows to make the base appear black, but for now, start with gray. (If you're not going for black, but for some other color, then don't worry about it; start with the color you want.)
When you select the dodge tool, as with all the tools in PS, you'll find all its settings across the top of the screen. The first one should look familar if you've ever painted in PS before, the bush setting. I'd recommend going with a very soft brush, maybe a hardness of 15% or so. As for the size, that will vary, depending on the level of detail you're going for. (The process will go MUCH better if you have a drawing tablet, by the way, since you'll be able to make natural, pressure sensitive, brush strokes. With a mouse, this is all gonna take you at least 10-20 times longer, no exaggeration, and you'll have to be way more careful.)
The second setting is the range. Pull down the menu, and you'll see you have a choice to dodge the highlights, the midtones, or the shadows. I'd suggest setting it to highlights, and leaving it there. Latex doesn't really have much in the way of midtones, and we're certainly not going to dodge any shadows (we'll be burning those).
For exposure, ALWAYS go with a very low setting. You can ruin an image very quickly with too high of an exposure. Normally, you want to keep it around 25% or less, but for latex, you can get away with higher settings. After a little bit of playing around, you'll learn what setting has the right feel to it.
The airbrush button is optional. Just as with any of the painting tools, having it turned on makes the "paint" continue to flow the longer you keep the brush in one spot. With it off, timing is not a factor; all brush strokes will have the same flow, regardless of how fast or slow you move.
3. Reflections To Match the Human BodyOkay, here's where we start making this thing look real. The highlights in the picture are not a great example of the effect we'll want to be going for, since the light source is from the side. Clothing in SL pretty much always looks best when lit from above. There is enough in the picture to give you an idea of where the highlights should be though.
Basically, any surface that has a top to it should get a highlight on its top. That means the breasts, the shoulders, the hips, the thighs, the knees, the arms, and any wrinkles. Paint with the dodge tool, in the general direction you want the highlights to flow (along the high edges of the wrinkles, down the thighs, across the tops of the breasts & hips, etc.).
You'll want to go over the same areas several times with the dodge tool to create the kind of super bright highlights that latex has. Again, a drawing tablet is ultra useful for this. If you're using a mouse, be really careful not to overdo it, especially with the stroke width.
Creating these highlights is where your effectiveness as an artist will show. It's gonna take some practice to make it work, so don't be disappointed if you don't get it immediately. Just keep thinking about the whole thing as a problem of light and shadow, not as latex, or as clothing, or as anything else, just light and shadow, light and shadow.
Once you've got the highlights in place, you may want to spend some time with the burn tool, placing shadows, and darkening all the tones (except the highlights) if you want a black garment. You'll find that the burn tool functions exactly the same as the dodge tool, just that it darkens instead of lightens.
There's not a whole lot more I can say verbally right now that would be really helpful. If you or your daughter have any questions on anything I've already said, feel free to ask, and I'll try to clarify. For stuff like this that is not just a question of procedures and button pushing, but real painting, it can be challenging to use just words to explain it. Hopefully there's enough here to get your daughter on her way.
Happy holidays. I hope this was helpful.