Use different hostname only for postfix

Hi,

I'm tying to set up my home server with Virtualmin. I've bought a domain name and set the hostname of the system to hs1.mydomain.com. The server is supposed to handle for this domain : - A mail server (postfix) - Several websites under sub-domains (sub-servers in virtualmin)

When testing for the spam score of my outgoing mail, I was told to create A record to the name of my server hs1.mydomain.com whereas I only did CNAME records pointing to my @ A record which points to my home IP address.

My question is : I'd like my mail server to have a different hostname (mail.domain.com) than the system hostname (hs1.domain.com). Is it wrong to only change the hostname in /etc/mailname/ and myorigin in postfix's main.cf and keeping all other hostname parameters to the system host name ?

Thanks. Regards.