Yes. I understand it and there isn't supposed to be any connection between a POP and an Exchange account. With the newest update of Office 2011 (14.3.4), I can now drag Calendar events from my POP account to my Exchange account. They then sync to my iPhone and iPad. Before that I could also drag contacts (People) between accounts and this seems better with the upgrade.
I think the problem is that Office 2011 was really ready for Prime Time when it rolled out and with Apple changing to webdav, the problem because not so much worse but horrible.
At the moment, things work. Not the way I expected them to work with a Mac product but I can force my way around.
I suppose the real disappointment is that MS does not offer any migration tools to move all data from POP to Exchange. You physically have to drag it which empties the POP account or holding down the alt key put a copy up there. This is a shame because small companies generally grow from POP to Exchange and there are no tools to facilitate that expansion. Oh well.
What needs to be done next is to get the calendar categories from the Mac Exchange side to the iPhone/iPad. That would be cool and very useful, too. The categories get into the Webapp but not beyond there.
Thanks for the concern but this isn't fixed but let's call it closed.