Neomail sender

As most of you may have noticed, there are two fields in Neomail\'s config page like these:

From: [INPUT FIELD] @ example.com
Reply-To: [INPUT FIELD]

This effectively allows any user of example.com to send email messages as if he or she was another user of example.com, which I guess may be good, or (in some scenarios, though admittedly not the majority of them) very bad - specially because Neomail leaves no trace of the original sender address among the message headers.

I proposed preventing Neomail users from specifying the From: field. I can\'t see the point of declaring a From: field other than the real sender address here. Nick said that anyway that should be done at the SMTP level. The problem is, I can\'t do that, because none of the headers contains the real sender.

If I change Neomail\'s config file, it will be overwritten in the morning, so..., does anyone have any suggestion?

Thanks.

PS. Please if you don\'t understand my English just tell me, thanks.