Seat bag that fits on aero posts?

I have a 'bottle' type thing I got from my lbs that fits in a standard wire cage, not fancy cages. It holds two tubes, three co2's, levers, a few $, zip ties, air chuck and probably some other junk that I can't remember.

I had the same problem with my new bike. I picked up the same type seat bag as I had on my old bike but couldn't get it to fit around the aero seat post either. I had to take it back and now am searching as you are. I'll be interested to see what others use.

I have a Pearl Izumi bag (sorry, not sure what style) that just fits on my Seduza seatpost.  It's a smallish bag - just enough room to tightly fit two tubes, two CO2 cartidges, the head for a CO2 pump, tire levers and a small multitool.