I have Mail currently set to show Plain Text messages in fixed width font so I know I'm receiving a Plain Text message vs an RTF one. Whenever I reply to a plain text message it always "masks" the sender's email with my own default font. So, if I send my reply in RTF, the message below mine (the sender's) is now in my default font rather than the fixed-width font I set it to.
So, is it possible to respond to a plain text message in fixed width font, and it KEEP that fixed width font while I reply in my default font? I know it will send as plain text unless I format something (like make a word bold), but if I do send it in RTF, I want the recipient to see that his message was in the fixed-width plain text font, rather than my default Helvetica font.

So, is it possible to respond to a plain text message in fixed width font, and it KEEP that fixed width font while I reply in my default font? I know it will send as plain text unless I format something (like make a word bold), but if I do send it in RTF, I want the recipient to see that his message was in the fixed-width plain text font, rather than my default Helvetica font.