The A12 was a carrier based, low observable [stealthy] sucessor to the A6 Intruder [program canceled in 1991]. Subsonic, with a large payload. It had nothing in common with [Y]F12 derivities. The proposed F12 derived attack varient never was assigned a DOD type number.
I found a couple of links
[link|http://www.habu2.net/a12/avenger2.htm|http://www.habu2.net/a12/avenger2.htm]
The AIM45 missile system developed for the F12 is an ancestor of the AIM54 system used in the Tomcat. [Most of the time, rules of engagement prevent effective use of beyond visual range missiles anyway]