Hey Scott,
Looking over the LabVIEW documentation I haven't been able to find any information regarding VLAN headers. From what I can tell this is something that is handled by the configuration of the switches in your network. Here are a couple of links I found when using google.
http://www.nwfusion.com/details/470.html
http://www.nwfusion.com/news/2002/0527specialfocus.html
I looks like the idea of VLAN is to allow computers to connect as if they are on the same network. I wouldn't think that would require any additional headers from the applications view point. The switches should take care of that.
I hope this helps out.
JoshuaP
National Instruments
