don't want to type @domain

[courier]

Hi all,

I've recently installed 
qmail vpopmail, vqsingup and sqwebmail.
on a Redhat 7.0  -  Everyting went smooth.

My problem is,
I do not want my users to have to type in the domain name 
at the time of login.

How do I awoid that ?

Thanks in advance
Mettavihari
Sri Lanka