mod_expires with mod_proxy

Hello everybody

I made some tests with mod_expires to work together with mod_proxy (or
mod_jk).
I was not able to get the "Expires" header through mod_proxy sites.
Local sites worked well with mod_expires.

I didn't find any information that this could work, or why it
shouldn't work.

This this a known "feature"?

Apache 2.2, Linux 2.6.16.13-4-default GNU/Linux,


Regards,

Synox