How do I add buttons to the WYSIWYG editor for custom BBCode

[patrickb]

I would like to add some buttons to the WYSIWYG for my custom BBCode. I figured this would be something many people would like to do since the users might not be aware of the custom BBCode on the site.

Could anybody point me in the right direction? Do i need to modify some files? Is there an API to add buttons or settings (which would be great!)? Did anybody do this before?

Thanks