Blender unwrap Map for texture Question

Hello, I was wondering if possible to use Seam for unwrap the UV map for make the texture, instead of unwrapping the mesh manualy, it was using the method show in this video http://blog.machinimatrix.org/2008/05/12/blender-surface-textures/#more-12 but I need a more precise method for make the texture, anyone if this possible and it is know where I can get tutorial for doing it, Thx for any help you can gime.

You don't unwrap the mesh to work with SL, the SL avatars already have UV coordinates assigned. To texture the av you paint toward the UV coordinates already assigned, you don't assign new coordinates.