[plt-scheme] send-mail-message

Hi,

I was hoping the someone can help me.  We have a cgi web app developed 
in plt scheme that uses send-mail-message to send email to users.  It 
works without any problems.  This procedure takes the following aurguments:

from-string
subject-string
to-list-of-strings
cc-list-of-strings
bcc-list-of-string
body-list-of-strings

[extra-headers-list-of-strings]

We need to specify a seperate reply-to and from strings.  Can 
extra-headers-list-of-strings be used to do this?  If yes, can someone 
show me how to create the header?

Thanks in advance,
Arend