You have imported a new external certificate into your server and ready to enable it for exchange smtp, pop3, imap. However after running the command you get an error message indicating that the PrivateKeyMissing.
The installation of Rollup for Exchange 2010 on SBS comes up with a blank page in OWA. The script updatecas.ps1 will handle the OWA and ECP updates. The UpdateCas script comes with the update rollup.