Replacing default BBcode?

[Bundle]

Hi, I'm just wondering if it's possible to change the way the default BB codes work? The main reason I want to is that, as far as I can tell, the [code] BBcode doesn't work! It still parses code inside the tag :erm:. I made a custom BBcode that does work, but because [code] is a default one, I can't name my custom one [code]. It's currently [code2] which obviously isn't ideal. So is there a way to edit the HTML replacement of the default codes? Are they hidden away in a file or template somewhere?

Cheers.