Hiya,
I have been developing on the MC56F8037 EVM using the USB TAP successfully. On Windows XP, mind you.
One thing I have found is when I create a new project, there is a button next to the build selector (right name??) i.e. where I can select SDM_pFlash / SDM_Simulator / Build all. When I mouse over it, it appears as "SDM_pFlash Settings".
Anyway, If I click that, in the Debugger\Remote Debugging selection, I have to select 56800E Local USBTAP Connection before I have any luck. If you select that, and click Edit Connection, just make sure the Connection Type is set to "USB TAP Connection." I didnt have to change any settings.
Failing that, check under edit\ Preferences - Debugger\Remote Connections that the USB TAP appears in there.
Good Luck!
Laurence