mailenable settings

[tmaxcon]

I am runing Plesk 7 on a Windows 2003 Server. The server is setup with the default mail settings after installing plesk. I have added my IP addresses to the white list for smtp relaying. I have received several complaints of mail getting kicked back as spam. Does each domain have to have postmaster mailbox setup. Is it possible to have Plesk automatically create a postmaster mailbox when each new domain is created. Any comments or suggestions on settings would be greatly appreciated.