[Dovecot] Default domain ?

Hello,

I'm in the process of migrating from qpopper to dovecot and I've stumbled upon the least expected thing: In qpopper I can specify a 'default domain', which will be used if an user will only issue his username (not the whole email address) when logging in. Because of this, the users in my main domain don't use the whole email address when getting their mail. I'd hate to have to call each of them and guide through their OE menus to fix this issue, so I must ask: Is there any way at all of specifying a default domain in dovecot ?

Thanks, Marius