That radio has to be a knock off of another model somewhere-I have never heard of it (flea market/eBay special?). It is still hackable.

The only thing I could find on it is one little blurp that is was made around 2004. So most likely, it is going to be just a grounding of the e-brake wire-whatever color that will be.

Just post pics of it (turned on if possible). Also include a pic of the wire harness. I am sure I can figure it out if you provide those pics...