The question whether or not Academy time counts towards military retirement comes up on AW every so often (the answer is no if you're wondering). Anyways, we always debate the question for a few posts, but I can't recall ever seeing a source to support the correct answer. While researching a related topic I finally found a source:
http://www.defenselink.mil/militarypay/retirement/ad/19_faqs.html#Q2
http://www.defenselink.mil/militarypay/retirement/ad/19_faqs.html#Q2