Note that (at least in 2007 w/RTCOMM, and I'd assume in 2008) you can set up the built-in VoIP/SIP client to connect to your Gizmo account (look up sipphone on the forums). Then, when a call comes in, it will use your nokia-selected ringtone, unlock the screen, etc - works nicely. To get to the dialpad from there, you click the "answer" button (obviously), then hit the menu, "call" (or maybe "file" - it's the first one), and choose DMTF Dialpad. Ta-da!

I use it, and aside from really bad echo (which apparently is better in 2008), it works great!