RDP Certificate for Vista

Hi,
if I enable RDP on Vista and connect via RDP to the machine a selfsigned
certificate is created and used for the RDP(S) connection. Is there a way to
select another the RDP certificate as in Windows Server 2003 SP1?
I deleted the selfsigned certificare and requested a Computer certificate
from a enterprise CA, but on establishing a new RDP connection a new
selfsigned certificate is created and used for RDP.
I think selfsigned certs offer a much lower security level than certs from a
companywide trusted enterprise CA.

Thanks!