I had some problems using the scripting engine to get the UVNC certificate loaded.  I found this article that will use a Computer Settings GPO to put the cert into Trusted Publishers.

http://www.bibble-it.com/2008/09/03/adding-trusted-publishers-certificate-with-group-policy

This problem effects Windows 7, and it can stop the installation of UVNC if you choose to install the video driver.  You get a prompt asking you to allow the installation from an untrusted source.  This fixes that problem.

I have attached the certificate in case you need it.  (rename to .cer)

Attachment