you need to contact AFAA to find out about this. Here is a link to their re-certification process http://www.afaa.com/continuing_education.htm. It may well be that an NASM certification may not be sufficient to re-certify with AFAA. They specify that some of the CECs have to come through them directly, and you can petition for the rest.
I had a similar situation with a water aerobics certification (of all things) and had to ‘petition’ two NASM specialty certifications (PES and CES) to satisfy their requirements! I consider this to be a cheap money maker for some organizations that certify. (Sorry for venting; it is a pet peeve of mine.)