Little front rack, the wee Crumpler is a perfect fit. picture at the bottom shows the 'gap' in the carry strap housing - there's one on either side, plus one underneath, and I'm thinking something attaching to these, then attaching quite tightly to the rack is the way to go. But needs to be relatively QR....
Untitled by blackpuddinonnabike, on Flickr
Untitled by blackpuddinonnabike, on Flickr
Untitled by blackpuddinonnabike, on Flickr