No, I didn't modify it but I did find an adapter for the receiver hitch to carry a chair. It is a Tilt-n-Tote by Wheelchair Carrier.
http://www.wheelchaircarrier.com/lifts/tiltntoteWheelChairCarrier.htmlI searched ebay and found one for $31 and it was here in Allen.

This is the view most other bikers have of a Valkyrie.

The carrier in the receiver and folded up.

The carrier out and ready to... carry!
We went wheelchair shopping today but ended up buying a collapsible electric wheelchair to make it easier to take her out and still allow her to be self-sufficient. As soon as we find a basic chair I'll be able to haul Mary around more often when we ride.
Thanks for asking HW,