This is not supported at this time. The only way to install the NI-VISA run-time is through the separate, standalone installer. National Instruments is aware that this is not the best way to redistribute driver software in all circumstances. National Instruments researching ways to allow customers to incorporate drivers more seamlessly into their installers.
Note that NI-VISA is not freely redistributable. You must ensure that each machine on which you install NI-VISA has a valid license for NI-VISA.
David Rohacek
National Instruments