Selling the setup, maintenance, modification, and hosting, of sub-forums
 

I'm wondering if charging a yearly fee to a customer, in return for creating subforum(s) for them (and providing modifications, maintenance, support, and hosting, therein), within my purchased copy of Vbulletin, would violate the terms of a Vbulletin license? I would not be reselling separate copies of the software, nor the software itself, as the charge would essentially be for a service, but it still seems a somewhat gray area to me.

Thanks for your clarification.