Any way to silence IM Notifications, etc?

Hey gang-

Is there any way to tell SL not to send notifications of IMs, etc? What I mean is I don't want the SL dock icon going nuts every second that SL is in the background- I will get to my IMs as soon as I can- I promise!

I even tried the app DockLess. This works in that SL no longer shows a dock icon or bounces it. But when run Dockless, SL instead throws up a Modal dialog with an Okay button every time an IM comes in.

I'm trying to find a way to run SL such that if it is in the background, it remains so silently. Perhaps a Terminal trick?

Thanks!