Windows mail signature font

I have a signature set up and marked as default. When I open a 'new' email the signature appears, using the font style and color I chose in the 'compose' window. However when I 'reply' to an email the signature appears in the font style and color of the email I am replying to, even though my reply text appears in my chosen font and color. Can anyone tell me how to correct this fault? If it helps, I have checked the 'insert signature in all outgoing' box and unchecked the box that says 'don't insert in replies and forwards'.