So you don't see any problem with properties and values etc in the AfterBuild task element?
No problem. We've reproduced that situation, and not found something special, excluding xml-comment flag.
If I specify Input files to something like "My*.dll" will that then cross obfuscate all the matching assemblies?
(Not specified in doc)
You should specify list of dll's (separated by ";") or Spices.Project here. Wildcards symbols aren't supported here.
Do you think this has anything to do with below line?
This line imports list of tasks especially designed for SilverLight, that you can use here.