You should be able to download a Virus C patch script from the
Access website.
Load this into your patch script folder, in the 'active' section
What version Cubase are you using?
one was is to set up a multi when working on a new project, and have one multi per project. Name the multi the same name as your cubase project. Now, you should have 16 channels of virus, across 16 MIDI channels in cubase.
If you are working in mutli mode, and have selected the names of the Virus patches from the bank select thingy in cubase, each time you start your project, the virus should be automatically on the right sounds, presuming you have all connections to the machine made, and all settings are correct in the Virus (Read the manual, it has all the answers)
Good luck mate~