problem with Chinese in signatures

[S.Lewis]

I use the regional language options for Chinese while
using Outlook 2000.

I have created a signature which contains both English
and Chinese. I have set my settings to insert the
signature in all new messages I create, but not in
replies. Sometimes in replies I do wish to insert the
signature, so I select insert/signature, or simply press
the signature icon.

Sometimes the Chinese characters in the signature appear
as "????" <question marks>; sometimes they appear
properly as Chinese characters. It seems to work for some
people but not for others. It may have something to do
with the font or other formatting used by the person to
whom I am replying.

Any ideas?
Thanks, S. Lewis