Thanks for the comments guys. In the actual hand I checked, he bet 45 and I folded.

I felt that part of the problem with repping the ace, is that I was probably only ahead of about a 1/3 of his range, and I would have had to bet too much to realistically rep the ace.

Maybe I was too conservative in those calculations though, and probably rerasing more preflop would have helped me know more about where I stood.