Why can't I retain sig formatting on replies?

[Patrick G.]

I’ve created an email signature in Word which contains various tex
formatting and an image, but when I reply to email messages, m
signature reverts to plain text with no image. This seems to happe
only on replies. Why? I’m using Outlook 2003. FYI, I’ve got th
signature set for New Messages as well as Replies & Forwards

 

[Patrick G.]

Well, I just checked, and it works for some replies, but not others??