I have my powermate to track forward and backwards as well as pause, and alt+tab.
Program the powermate in its driver program to use a set of keys that arent used in any program you might be running externaly.
Then map the keys you programed to the functions you want them to use in ME.
There is a bug in the current version of the powermate drivers, that will cause problems if you try to use the down and rotate functions. If you use them, when you release the knob, it will preform a click function. (I hope thats clear)
The guys at griffin have told me that they hope to have new drivers out to fix these problems by the end of the year.