I have bought an UC SSL certificate from Comodo for my Exchnage 2007 services SMTP, POP, IMAP, IIS services about a month ago, since my current Digicert certificate will expire in a week.
I attempted importing the certificate with the command line they provided:
Import-ExchangeCertificate -Path c:\exchange_example_net.crt | Enable-ExchangeCertificate -Services "SMTP, POP, IMAP, IIS"
After issuing the command line on the Exchange 2007 Shell, apparently it worked.
Then I issued the Get-ExchangeCertificate cmdlet to verify it was imported correctly. I can see that the certificate was imported but it is only showing POP and IMAP as the services registered.
I called comodo and apparently they don't know why this is.