Unique username generation when creating new user via FIM Portal?

Hi,

Is it possible to create a new user using the FIM Portal, and have FIM create the unique username upon submission of the request in the Portal?

So effectively, when you create a new user in the Portal, the 'accountName' attribute would not be a mandatory field and therefore removed from the GUI using RCDC , and instead be generated based upon the unique AD username rules.

Thank you.