[stunnel-users] logging real client IP in Apache

I have an Apache server serving only HTTP requests on port 80 and an stunnel daemon on the same server listening on port 443 and tunneling HTTPS requests to Apache. Is there a way for the client IP to be passed on to Apache so that I can capture and log that instead of the IP of stunnel, which in this case is 127.0.0.1? Ability to add a variable to the HTTP header would be perfect, but any other suggestions to solve this problem are welcome.

Thanks! Stoyan