You have a couple of options. First, check with Prema if they have a driver. Second, you can request that NI develop a driver for you by going
here. NI does driver development based on demand and there is no guarantee that they will do it for you. Third, you can pay someone to do it for you. There is a worldwide network of third-party LabVIEW developers called the
Alliance Program. Forth, you can develop the driver yourself. LabVIEW 7.x has the Instrument I/O Assistant that you can use for basic tasks htough it's not as flexible as a true driver. You can also find templates and instructions on creating your own driver
here. There is no specific template for a switch or scanner but these are generally pretty simple and looking at a driver for something similar (i.e. HP34970) should give you an idea on how to get started.