Oliver,
I'm not sure if there is a VISA driver for that tuner card. By VISA I'm assuming you're referring Virtual Instrument Software Architecture. VISA deals with VXI, VME, PXI, GPIB, and/or serial interfaces, re: www.ni.com/visa
I did find a posting of a VI for the tuner card. If go to www.ni.com/exchange and look under the Vision category somebody recently posted a zip file. The title of the post is �Full color image capture using low cost hauppage tv tuner.�
Kamran