buckworks - 6:51 pm on Mar 16, 2013 (gmt 0)
Others might have other suggestions, but here's what I'd do:
Go in to the "Settings" for your enhanced campaigns, and look for the adjustment called "Change mobile bid adjustment" (which IMHO ought to be a lot easier to find!).
Apply a percentage reduction for "Mobile devices with full browsers", in this case probably the largest number the system will accept.
That will reduce the bids for your ads on mobile phones so they'll appear less often on mobile, and maybe not at all depending on the competitive landscape.
Next, make a new campaign and do the reverse: apply a percentage increase for the mobile bid adjustment. That campaign would use the landing page(s) for mobile devices.