Hi vespe,
The Treo 700w is a PocketPC Phone Edition, not really a Smartphone, and Smoresoft Sudoku doesn't officially support PocketPC's yet. However, check back sometime after the New Year for a PPC edition which will better support the Treo.
I haven't yet found a way to determine which letters map to the numbers on the various Windows Mobile device keyboards out there. Device manufacturers seem to be putting them on different keys (e.g., Treo 700w vs. Moto Q vs. Samsung Blackjack). Right now, the game only supports the Moto Q layout. I'll look into options for supporting arbitrary keyboard layouts in the future.
I'm curious about why you would want to toggle full screen mode, since the menus should be fully functional in full screen mode. Can you describe why you want to do this?
Thanks,
-David