Wow brother!
They are not making it easy on you are they.
To get into the OSI-7 layer model at level 2 is not going to be easy.
There was some recent discussions on the LV list where someone had posted a "sniffer". This will let you look at everything, but writting, that is another story.
Have you got some way of testing this device and possibly using the "sniffer" code to figure out what protocol they are using.
Even if we can figure that out, we still need to know the packets format themselves.
Can you get any doc's from the people that make the widget that may help?
For the time being the best I can do is urge you to find that posting re:sniffer and try to figure it out t
hat way.
Jeffrey Travis wrote a book Internet applications in LabVIEW (?) that was real good.
I recomend it.
I can not tell you what is involved in writing to layer 2 of the OSI-7 layer model.
Doing what I can to help,
Ben