How long for ab sculpting?

I have been at this training thing for 3 months now, or so, and one thing I was wondering is how long does it take before you start to get real nice abs?  I mean, when I started, I was at 12% body fat and I have yet to get tested now to see how I am doing (I wanted to be at 8% by the end of the year).  What I have noticed is that sometimes during the day, I have decently defined abs (oddly enough, like when I have something on my stomache) but other times during the day, the only definition I have is just the line where you can tell where the lats stop and abs start.

I guess what I am wondering is about when do you start seeing perminant results or what is the deal with ab definition?  I guess I just don't want to be looking for some kind of definition that doesn't really exist...

ab muscles are flat, work on being fit and enjoy.