It is impossible to map <Super><Shift>1 to a application.

To reproduce:
1. Go to Settings -> Settings Manager -> Keyboard
2. Click on "Application Shortcuts"
3. Click on "Add"
4. Input "xclock"
5. Press Super (aka "Windows Key"), Shift and "1" (not on Number-Pad)
6. Now press Super, Shift and 1: Nothing happens

The problem stays the same for all numbers, so its not possible to map Super, Shift 2-0 to a application.

Very strange fact: These shortcuts work in the window-manager, but not in application shortcuts.

Version: 4.8.0
Distribution: XUbuntu 11.10