You can use the standard binaries to install NetBackup in a virtual environment. The following 2 documents detail NetBackup's support in a virtual environment:
NBU 6.x: http://seer.entsupport.symantec.com/docs/312604.htm
NBU 7.0: http://seer.entsup...
I think the easiest way to do this would be to re-install NetBackup on that media server and choose the master server option. Once you have the software installed, configure your robots/drives, and perform a catalog restore