How to uninstall out-of-browser silverlight 4 application programmatically instead of using the contextmenu (e.g. if I want to replace the context menu)?
Edit
This isn't an answer, but it's related to your issue. On the official Silverlight wishlist, I added the ability to do this quite some time ago. Luckily, quite few users agree. With enough votes, hopefully it will appear in a future version of Silverlight.
http://dotnet.uservoice.com/forums/4325-silverlight-feature-suggestions/suggestions/410706-greater-control-over-installation-in-oob