filtering of proxy response

Hi,

The deflate filter does not seem to have any effect on the content fetched
from
an origin server when Apache is configured as a proxy. Look at the code, the

proxy module does seem to have an output filter chain. However, what the
user
agent received is the clear text, even though the deflate output filter has
been
turned on for the proxy. Can some one explain why?

Thanks,
Steven Zhou