I've adopted your sample report demo (SSRSReportDemo.xaml) and tried to run it in my windows store app. I'd like the user to enter the report name, credentials, etc. and after pressing a button the report gets rendered.
I copied the following source from your sample, trying to dynamically load your Adventureworks-example-report:
As soon as I try to replace the hard coded credentials in the Report_Loaded-Event, the data isn't loaded anymore. It doesn't matter if I run the code in the UI-Thread, as Runasync, or if I get the username/password from member/static variable. Even when I tried putting the username/password in a constant - the data isn't loaded anymore!