I remember creating air units that could only attack other air units, because I was really interested in WW2 dogfighting back when Red Alert came out (I was also 11). You won't be able to make complex total conversions just by dicking around with an ini file, but you can do quite a lot with it. Otherwise, I've tested a few other variables and my changes showed up in the game as expected.
I seem to remember having difficulty with that back in the day, too (maybe try editing the 'dog bite' attack instead). For some reason, editing the attack dog entry doesn't work.
