mod_proxy + mod_ext_filter together

(newbie asks here)

I'd like to filter information passed via proxy.
I loaded mod_proxy + mod_proxy_http
and mod_ext_filter.

The forward proxying works OK
but mod_ext_filter kicks in only when
accessing local files - the ones fetched
via proxy are ignored.


The configuration looks like:
--------------------
ProxyRequests On
ProxyVia On

ExtFilterDefine my_filter mode=output cmd=my_filter.exe
preservescontentlength
<Location />
SetOutputFilter my_filter
</Location>
--------------------

I know it is probably full of holes but I use it
just to set up infrastructure.
The mod_proxy + mod_ext_filter looks
as handy combination.

My aim is to have tool to filter content,
as much separated from Web server/proxy
implementation as possible.

/Pavel