Ax,
The Measurement Computing web site talks a bit about LabVIEW compatibility. I am assuming that when you install the driver for your GPIB board that it might also install a set of VIs that you can use with your board in LabVIEW. Either that, or they may at least provide some VIs that you can copy into LabVIEW yourself. However, to use VISA you will need a copy that supports your card. NI-VISA has explicit support for NI, HP, and Agilent cards. Though there might be some way to make NI-VISA work, it is possible that Meas. Comp. has their own version of VISA that you can install that will integrate its own VIs into LabVIEW.
Alan