Hey Chris, I have the same set-up here. From what I've been able to determine in the past, you need to go to File > Document Settings > Units. In Rounding Style, choose Fractional (if that's actually what you want, I assume?) and set your precision.
You should also triple-check that you've set your screen origin / screen plane / anything else you can find that defines "0,0" to be exactly where you want. Otherwise you'll get weird results (lights that are drawn at -437'3" are common in my experience). I read somewhere else that this was worked out in VW2012, but I haven't gotten there yet.
One thing to note: This has always worked great for me in the past, but the particular document I'm working with right now, the rounding is all screwed up. So my guess is there's some third thing that I'm going to wish I could find to make it work truly seamlessly, but this should get you in the right world.
-Matt Pumplin
ME, Hangar Theatre