RhinoFish - 3:50 pm on Mar 14, 2012 (gmt 0)
run them in separate campaigns so you can discern QS issues (and more).
check that your LP is optimized for mobile, try G's gomo tool to check it.
experiment with WAP ads to reach cell phones that don't have full browsers (careful, your goods / services need to convert via phone).
add click to call extensions to your mobile campaigns, it'll raise your CTR, and therefore your QS.
if you're not showing at all, get an expert to review your account - something sounds amiss here.