I think I need to know a little bit more information about what your asking. Is this for ALL skins, or is this for a skin you're creating. Because if it's for a skin you're creating, you will need to make sure that your taskbar button images are large enough to accommodate the taskbar, and you will need to make sure that the text margins on the taskbar buttons have enough pixels added to them.
If you're just talking about all skins in Windows 7, you would follow the steps I outlined in my previous post.
