Yamaha DTXpress/DTXplorer/DTXtreme

I recently purchased a DTXPRESS II set. I love it (especially
living in an apartment), but I find that after a little while my
right hand becomes extremely sore, so much that I can't continue to
play. This doesn't happen on my regular set at all.

I've tried using Zildjian's Anti-Vibe sticks and they seem to help a
little but not that much. Anyone have any thoughts/suggestions?