I actually use Pageline PlatformBase, together with two mobile plug-ins: WordPress Mobile Pack and WPtouch. They apply to all themes, and based on Mobile User Agent (Symbian, iOS, Android, Blackberry, Windows Phone 7, Palm) info mobile userinterface is shown. Even my pages are in Finnish, some pictures/examples in English: http://doaudit.fi/bl...mobile-example/
WPtouch free version does not give iPad customisation but if you have iPad, try with Safari http://www.doaudit.fi/
and you see what I mean by WPtouch Pro plug-in.
Hopefully explains how to use "mobile theme customisation". I use Genesis platform also, Pagelines and Genesis both handle extremely well mobile issues.
best regards Jari