Email accounts for addon domain?

[fishfreek]

Is it possible to create email addresses from an add on domain? I have a client asking me this question. Basicly lets say their main account is domain.com and they have an addon domain of extradomain.com. They want to setup e-mail accounts that would look like user@extradomain.com Where extradomain.com is an addon domain of the domain.com main account.

[fwwebs]

As a general rule, Yes.