INteresting....can you take a photo ?
They have FOUR pages in the book just for that:
www.avigex.ca/xport/roofantenna2.jpg www.avigex.ca/xport/roofantenna3.jpg
And yes, I think this camouflaged antenna is not the best for distant reception as I get much better performance from my other cars with an external antenna...but I live with it..and it is saved from damage in car wash....
I think any external "normal" antenna would be as good and probably better than that. SINce the roof is plastic, I would even try it inside just for a test.
I have not removed the radio yet but from the drawing it seems it has a standard antenna connector.... and intermediate connectors behind glove box so you do not need to actually remove the radio..