how can I delete maiulboxes on e61

Hi All,
got a new e61...could not get blackberry email working for a few weeks
so I set up normal mailboxes.....now I have blackberry email working I
cannot see how to delete the old mailboxes...there seems to be no
delete function...can any other e61 wiz assist me?

Also,
the blackberry mailboxes take the name of the email address....and they
would look better if I could name them myself....is there a way to do
that? I have not been able to find that either...

Thanks

Peter