Overwrite HttpResponse from uncontrollable site

hi,
I want to submit a form to some url say "www.xyz.com/abc", now after i submit the form with all relevant and required details the form is submitted and the work is being done, and a response page is shown up from that site.
the actual problem is here, when i submit the form to a url on which i have no control, it sends me another response page, i want to overwrite this page with my own page saying "your work is done" i.e., i dont want that page of the uncontrollable site to comeup, but to have my own page instead.
-santu

To hide the response from another server ,one way to go is:
Create a frameset with a hidden frame , and set the submit target to that form.
ie <form action= xxx target="myhiddenframe">