I feel silly sometimes when I post a reply without reading the 2nd or 3rd page of a thread so I understand how you missed it when I said I bought something bigger, stronger, heavier, etc.
But to answer your question, when I went to trailer dealers I often heard stuff like "my liberty towed 3500 lbs easily" or "the tow package is just a brake controller and we can install that". The language in the 2012 Liberty owner's manual denies those possibilities, as did the MOPAR parts people. However, being an american infused with the history of innovation and ingenuity of my heritage, I asked if a particular modification was ever tried. I appreciate all the advice I've gotten and I'll be popping another question somewhere else soon.
I just have to say, though, after 2 trips to the undeveloped property, the Econoline is no Jeep. I feel no shame at all for wishing I could have a little bit of both.