Convince Firefox to send an If-Modified-Since header over HTTPS

Question

How can I convince Firefox (3.0.1, if it matters) to send an If-Modified-Since header in an HTTPS request? It sends the header if the request uses plain HTTP and my server duti

Answer 1

HTTPS requests are not cached so sending an If-Modified-Since doesn't make any sense. The not caching is a security precaution.