xandmail as default webmail

[m.abrile]

Hi, I have one question, on plesk 10 if I change from horde to atmail, when customer type webmail.domain.com go direclty to webmail login page, if set horde or atmail.
I add Xandmail as therdyparty webmail with url as http://domain.com/web2cs, but if I try type webmail.domain.com i receive errore page, otherwise I go in panel of customer, inside mail section and i click on the left of email on webmail icons and xandmail open fine.
Where i wrong ?? whare is right way to install xandmail as default webmail in plesk 10 ??

Thanks