using mutt with postfix and localhost:25

[Globe Trotter via Mutt-users]

Hi,

I have an account where I need to send email through localhost (with port 25). 
I am using postfix currently, but I do not know much. Anyway, on sylpheed, I 
used to say: localhost:25 as the SMTP server and life was good. So, my question 
is how do I set it up for this account to use SMTP server localhost:25? (The 
other accounts are personal and will use gmx, etc, SMTP settings). I have been 
using postfix because my work email uses postfix as given by my sysadmin (I 
think that it changes the relayhost name) and perhps the same can be done with 
something like msmtp but i do not know.

Thanks!