For some reason the RFB boys don't see any use whatever for the attack map. So they haven't hooked it up to any function keys, choosing to leave the stock keyboard layout. Actually, the real sub jockeys wouldn't shoot a torpedo without comparing TDC output to the plot, and that's what the attack map does.
You can still get to the attack map with the command button bars. Or if you would like a keyboard layout that makes much more sense you can load up my
TMOkeys, which gives you the venerable TMO keyboard layout (very similar to SH3) plus shift-i for "some officer or other, please identify that target."