Solved this problem for my wife: BlackBerry Desktop Software for Mac OS X does not support CalDav MobileMe calendars. She no longer uses a BlackBerry.

Me? I’m planning on resolving this issue for myself by dumping my BlackBerry in the late June/early July time frame.

BlackBerry Support has only been able to tell me that they don’t know when or if CalDav MobileMe calendars will be supported, but keep checking for updates. Great.

I’ll give the Support people the benefit of the doubt on this issue and assume they truly know nothing. But my guess, and this is truly complete speculation, is that BlackBerry will never support CalDav MobileMe calendars. RIM is busy circling the wagons in the corporate enterprise market which is Windows-centric. An issue for individual consumers on a non-Windows OS just isn’t going to get funded.