Unfortunately, it looks like we have an error in the protocol manual, as you can see in the reporting style description, move events are not reported at this time.
The best option I can think of at this time for a slider would be to use down/up reporting in coordinate mode. Unfortuantely, it will only update once the movement is complete rather than the dynamic slide effect you are attempting.
I have asked our Engineering department to look into the possibility of adding a move response. As you may know it is available on our GLT line, but the GTT has a few more layers of programming that aren't working together right now. If we can put something together you'll see it in the change log for one of our easy to install firmware updates.