Does trailer hitch interfere with "Side Assist" in 2011 A4 Avant
 

I'm close to ordering a 2011 A4 Avant. I'm getting the Side Assist. I race bicycles and spend 90% of my time on the freeway with a hitch-mounted bike rack. Roof is not an option for bikes: I've proven myself incapable of remembering there's a bike on the roof when I pull into a garage...

The dealer tells me I have to disable the side assist when I have the hitch mount on the back. I sense uncertainty in their answer. I wanted to confirm that on the forum. I can understand disabling the feature where cars coming up on your rear set off "Side Assist", but it seems like the lane-changing warning could be enabled still.

Question: Does anyone know whether and how a trailer hitch on an 2011 A4 Avant interferes with "Side Assist".

Thanks in advance,
Rich