Control surface woes...

How is it communicating? ACT or it's own protocol? Is there a way on the keyboard to stop the mod wheel sending MIDI data out?

I wondered whether at some point you've mapped the mod wheel to the track 1 pan. Sounds like that may be what has happened. AFAIK there's no way to remove a mapping but I think JohnT was asking something similar a while ago and IIRC he edited the xml file directly.

I've never tried it but it might be worth waiting to see if he chimes in here or PM him perhaps.

I don't know what you are using for a synth.
However
Within alot of synths they have internal routing for CC (constant controllers) depending on how the programer wrote that particular patch you are using.  You would need to verify by looking at the synths CC internal routing for the patch's program.
 
If we are talking about that kind of a synth (Like Dimension Pro).  If that is the problem you would just need to reprogram the patch and save it as a new patch.
 
Hope this helps.