One of Gau's rages not working?

[,,,]

I'm playing FFVI Advance. I got Gau's "Tonberries" rage, and when I go to skills-->rage on the status screen, "Tonberries" is indeed listed in the very last slot. However, I can't find it in battle. I looked very carefully many times and it just doesn't seem to be there. Anyone else getting this?

btw, I'm using a rom. Yes, I steal things, and I don't care.

[Jowy]

That rage never worked in the original, unfortunately.

[Cruise Control]

Just mute Gau and use Intangir.