NXT plug-in on Dig. Sidecar: How to interface??

[RoboMaster]

I have seen multiple times in FIRST programming and electrical documentation (and visually by looking) that there is a port for a Lego Mindstorms NXT sensor on the Digital Sidecar. There are also what I believe I've read to be pins where you can wire up more ports.

This is great and all, but does anybody know how to interface to the port/plug-in?

There are no LabVIEW VIs (we are using that for programming) that get data from this and it doesn't look like you can open up a digital reference to that port; it isn't listed as one of the ports to choose from to open/get info from (at least I'm pretty sure. I believe I've checked that before) I've thought of maybe using the LabVIEW NXT toolkit that you can get from National Instruments to program the NXT with LabVIEW, but that is meant for the NXT itself; the ports that you can select discribe NXT ports.

Does anybody know how to interface to this port and where I can find documentation on this? Especially for LabVIEW, because that's what we're using. (I thought this was a topic not necessarily about LabVIEW, so that's why I didn't post under the LabVIEW sub-topic) Thanks, it's not super urgent, but I would like to know.