OWA has been the holy grail for me as well. A real pain!
Plain old PIE doesn't work, MultiIE doesn't work...the only browser I could get to work correctly (albeit it really slow) is Thunderhawk. I don't like the interface of Thunderhawk or the screen presntation 'fake' VGA....but it works until I can find an acceptable app. I won't buy an app like Netfront if the features are not all there in the trial version!