[msmtp-users] changing From: when mail sent with different smtp server

[Joseph LP <ootput@...20...>]

Hello,

I've a fastmail.fm account that does not provide smtp login. I've resorted to
using my gmail account's smtp settings.

As I do this, recipients of mail from fastmail.fm account (via msmtp and mutt)
only see From: as from gmail account.

My relevant .msmtprc and .muttrc settings are as follows, respectively:
- .msmtprc
account user_at_gmail
host smtp.gmail.com
from user@...20...
user user@...20...

account fastmail : user_at_gmail
from user@...201...
- .muttrc
set from="user@...201..."
set envelope_from_address= "user@...201..."
set use_envelope_from=yes
set use_from=yes
my_hdr From: user <user@...201...>
my_hdr Reply-To: user <user@...201...>
-

What should be done to remedy this? I'd like mail sent from fastmail.fm with
From:user@...201..., regardless of the smtp server used to send the mail

Regards