I have never personally tried to program one of these devices so unfortunately I can't tell you how difficult it will be to program one of them. However, I did check out some information on programming the card at the company's web site. You can reach it at: http://www.crsltd.com/catalog/vsl/
It appears that they have setup an API layer so you should be able to control it from LabVIEW. I suspect that they offer dll's that contain functions you can call. So in LabVIEW you would be able to use the call Library function as the building block for your program.
Hope this helps a little.
Matt Kisler Applications Engineer National Instruments
I think you're asking about features in LabVIEW for calling external code - the following is the documentation for that topic and should answer most or all questions that come up: