I use Gmail with Mail.app. As you know Gmail allows replying mails as someone else (by changing
From header of the sent e-mail). If you don't know, you can register multiple mails to Gmail (your personal mail, work mail etc.) and you can send mail from them from one account.
Let's say you have 3 mails registered in GMail:
firstname.lastname@example.org. Your account is
email@example.com in this case. When you use GMail web interface, if you receive a mail redirected from
firstname.lastname@example.org, when you press Reply, it sends your mail as
email@example.com (or you can choose other accounts to mimic one of your e-mail addresses as sender).
However when I'm in Mail.app, I'm only able to send mail as
firstname.lastname@example.org, any ideas to solve this?