For a sample project about your first questions you can refer to this forum post: http://www.telerik.com/community/forums/silverlight/window/how-to-raise-event-for-my-scenario-using-telerik-s-rad-window.aspx
. In it is illustrated how to access one RadWindow from another. You can use the same approach to achieve your goal.
As for the second question: unfortunately, this is not a supported scenario by Silverlight. You cannot show a Silverlight RadWindow outside the Silverlight plug-in.
Hope this information helps. If you have further questions please let us know.
the Telerik team
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