New unit woes - pack won't load in game

[mikoyan99]

I've been working on new units for my confederacy mod; as it's going to be a bit steampunk, i've created a "Smutts Torpedo" launcher, which is a simply a mod of the amstrong gun that fires torpedos rather than shells, from a torpedo tube. It's a weapon from Space:1889 if you're interested.
I've got this working in game with a simple mod of the armstrong gun (by writing directly into the patachxx.pack file), but i'v tried to create it as a new unit in it's own pack file and it doesn't show up. I've checked everything I can think of, and all of the names tally up, but still no result. If someone could take a look, that would be handy.
I havn't deleted the other entries yet, as i'll be adding more units and variations before i'm done, but the ID's are:
Unit:
Boshin_smutts
Gun:
boshin_smutts
projectile:
Boshin_smutts_shell
-Matt