Neither my road bike (Scott Foil) nor my TT bike (Scott Plasma) has any sort of round tubing, and i'd like to know what other mounting options are there, in particular ones that would play nice with a saddle bag.

The Foil also has the issue that there's no place to attach on the saddle rails as the clamp takes up the rear portion of the rails.

Has anyone found satisfactory seatpost mount that could accomodate foil-shaped seatposts?

Many thanks in advance