User creation for Marketpress

Sorry for so many post but I'm not finding any definite answer.
Is there any way to create a Wordpress user for a new sale with Marketpress?I would like to let my buyers use/post in bbpress(integrated) but this is not being possible as I don't see any option for Marketpress to create a new user account against a sale by a 'new user/client'?
Even if it could create a new user in Wordpress as 'subscriber',then they would be able to get mapped in bbpress and best would be if we have the ability to define against which role they are mapped(subscriber,contributer etc).
Kindly show me the forward path if this feature is inbuilt or not.
Many thanks in advance.