Autogenerate Username at registration

hello, I have a client looking for a membership solution. the main requirement is that the username is autogenerated and follows a set pattern 'UN12345' and a temporary generic password is created at the time of applying to become a member. once the membership is approved, the login details will be sent to that new member, and they will be prompted to change their password on logging in. is this something that is possible with Emerald 10?

thanks robb