The best place to start for instrument drivers in on NI's
Instrument Driver Website. On the left-hand side of the page, click "Download." This will allow you to search through their huge database of LabVIEW and CVI instrument drivers for you to use. They have the Wavetek 395 driver available. I have not used this one in particular, but I assume it will integrate with LabVIEW well as it came from NI. That will give you a good start. Good luck!
J.R. Allen