Signature code

[RustyDogma]

When a signature is posted there's a line and the user's sig

______________________________________

My sig is here.

What I'd like to do is add and additional line to the signature that uses BBCode:

[color=blue][b]Forum USER NAME[B][/color]
_________________________________________

My sig is here.

Where can I find the part of the template to do this and how can I use BBCode rather than HTML?