[ale] sendmail configuration

[Ev]

I've got a question about sendmail that I hope someone canhelp with.  My machine
is configured with a host and domain name that isn't my ISP's (I use a domain
name of my own, whereas I use Mindspring as my ISP).

Some times when I send an email, it gets bounced back because in the transfered
header is

Received: from pop.mindspring.com by mictali.aegol.com (fetchmail-4.3.2 POP3 run by jemcdevitt)

and the destination of the email checks and discovers this domain isn't valid,
so it rejects the email.

What setting do I change in send mail to reconfigure the Received: line?  I've
go the masquarade set so that my local user name translates correctly for the
Reply to and From lines, but I'm not certain about the received line.

Would appreciate any pointers.

Thanks,

Ev