Even on Windows XP Firefox only gives basic mode. You really need IE 5.01 or preferably 6 (or 7) to use the premium mode. That's by design. See
So run Windows on your Mac and you're done.
I find my self using OWA more and more - mostly as I'm a Mac user and I don't like how 'Mail' plays with Exchange Server or how Micosoft Office for Mac works in general.
Is there anyway I can get full access to OWA on the Mac as opposed to using the not-so-great condensed version that FireFox defaults to?
I can use IETab for FireFox on Windows, is there anything like that for Mac?