> ah, ok, then the problem is that the application is a *client* (and it
> doesn't reside in the server like I understood).

yes, sorry it wasn't clear in my first post

> then the problem is will the application follow the rule you set for the proxy or will he
> still connect to his own server (if is hardwired, is hardwired)?

they can set a proxy server in the app configuration, I tried with a
simple debug proxy and I correctly see their connections.

> If he follow the rule of the proxy then you could fool it by using the
> proxy solution, otherwise I don't see a big chance of doing it.

yep and this is what I don't know how to do. I'm trying to set up a
proof of concept to show them we have a temporary solution until we
rewrite the whole application :-)

Looking at the (poor) docs I found online I need to use the forwarding
mod_proxy feature to let the user set proxy.mydomain.com in their
application but then need something like the reverse mod_proxy feature
to transalte transparently the legacy app request to xyz.olddomain.com
to fake.mydomiain.com.

Any hints? Thanks a lot!