I am installing a reverse proxy on Apache. For basic cases, everything
works fine. When I do a simple redirection, like for example
ProxyPass /server/
ProxyPassReverse /server/
no problem.

I also succeeded doing a "redirection" to a script like for example:
ProxyPass /server/
ProxyPassReverse /server/
again, this works, I see the page.

My goal is now to pass additional parameters to index.php in sort:
ProxyPass /server/
ProxyPass /mail/

as soon as I pass a parameter to the page, I receive an error that the
page does not exist.

For this reason, my question is now:
Is it possible to redirect on the reverse proxy to a page and pass a
parameter to thisone?
If yes, how can it be done?

Many thanx in advance.