I bought a tail light that came with a bracket to mount the light on my seatpost. Trouble is, my seatpost only extends about 2 inches from the seat tube and I have an under seat wedge (bag) that fits in the same area. Is there an auxillary bracket available that would attach to the seat post and extend downward (under the seat bag) to provide a clear mounting location for my tailight? Any other options other that returning the light (and/or bag or bike) and starting over? — Thanks!