Font in the head of answer/forwarding

Good morning,
I’d like to buy your client and use it for my 6 email accounts, but I’ve a problem:
how is possible, in case of answer or forwarding of an email, maintain, in the line _ From, To, Sent _ and _ Subject, _ the font selected by the sender (original font) and not use the font that the user has selected for new message (in my case Cambria)?
Thanks in advance, Alessandro