So, then the trigger for the switch is occuring inside the DM10. In that case, a simple spring switch would work, yes? Off, On, Off.
Ahh... but as I look through sweetwater's site, I don't see a "simple" off, on, off switch. Hmmm. And you'd want two switches to go Up and Down, right? (you may have mentioned that above).
if I come across anything, I'll post.