You need to use the latest SIB to apply any real taskbar skinning in 10.
I think you need to use this stylehack to add new taskbar elements to edit in WSB:
https://www.vistastylebuilder.com/forum/index.php?topic=2240.0I don't use SIB so I don't know the details about what has changed.
You might be able to find out more information at the MSFN SIB forum or at Virtual Customs.