Wunderground is receiving the data as a text string via an HHTP GET request. The Wunderground upload protocol doc page i linked is the format that the station uses.
I believe the reason why there are no docs for an API is because the station is designed to connect to a server somewhere and not have client connections to it (Other than a Web browser for configuration).
So my idea is to (for now) redirect where the station uploads to. The idea being to have the station send the data to your tablet in the same format it would otherwise use to send it to WUnderground.
This way you would be receiving the data as a text string, Which might be easier to parse than an XML file.
I was looking into it earlier for their WiFi version, so to get a better idea of the angle I'm coming at it from Look at this thread:
http://www.wxforum.net/index.php?topic=22605.225You'll need to scroll about halfway down the page to where I start responding to NETO's question.