Create User using RBAC on Exchange 2010

I have created a managementRole based on Mail Recipient Creator, also i have removed some cmds. After that i have created a new Role Group  and Role Assignment. Before i finished i have added a member into that RoleGroup.

Is working, but i can't create a "New-mailbox user" using RBAC, Will i need to do something else? Or i need use the EMC to create it?



Suggestions?