One other thing - and I have no idea why this happens, is the difference between importing a cert using the MMC import functionality and launching the import by double-clicking on the cert file. The behavior looks the same, and I spent an hour on the phone with VMware support not too long ago trying to figure out why my cert wasn't working, and it turned out to be just that - I was double-clicking on the cert file and doing the import into the cert store instead of doing an "All Tasks/Import" from the MMC. Once we did it the "right" way (importing using All Tasks) it worked. I have no idea what's different, but something.
Geoff