Registration Confirmation Email


I am wondering if you can help me customize the email a user receives after registering with ultimate facebook. I am using multisite and buddypress and requiring facebook registration.

Right now the user receives and email with the subject "Your username and password" and the contents are just

Username: USERNAME
Password: PASSWORD
Login Link

I have searched everywhere but I cannot find where this email is generated. I am hoping to include a link to the site they created and some welcome information.