Before you go too far with your development, have you taken into account that the 'end of life' for the v2 software has been announced.
It would probably be better to do this with a v3 forum at this point in time.
phpBB: The All Important Rules - Bertie Bear 3.0 - No support via PM system - use the forums please.
phpBB v2: Retirement (1/1/2009) : phpBB v3: Read Me Topic - Custom BBCodes - Support Template
Matthew 7:7"Ask and it will be given to you; seek and you will find; knock and a door will be opened to you."
My Links: MS MVP (Consumer Security) - Malware Removal:University - Own Forum: Custom BBCode testing