Oh how I love certificates...
I've imported the cert as a .CRT with no errors from the exchange console.
I've also (alternately) imported the cert as a PFX from the MMC plugin as the "computer" local account.
Regardless of which way I import the cert; in the MMC and the Exchange admin console, I still see three Exchange related certs.
But only in the MMC do I see the new cert I've imported. (I've also tested this wildcard cert on other hosts)
I've rebooted to no effect.
Any thoughts or assistance appreciated.