Actually I believe starting this year they are allowing IRR HPSP students to get a .mil e-mail address. I am a D1 and just started school and have my .mil address set-up. Contact your recruiter, for me when accessing MODS eventually an information screen came up regarding setting up your . mil address, but I think most of that was set in motion by the recruiter.
For anyone in the Army, you can go to the MODs website, under the General Info Tab, the menu item "Instructions for Annual Physical" there are also instructions on how to set up your AKO account that comes with a .mil email address.