I have the same question. I'm not sure if I understand your reply. In my case, I have a form that collects some info, then I need to validate the form, so I pass the info to the php script and validate it. From there, I want to post the data to a different server (namely Paypal) without the user having to press the submit button on another form. Something like this:

<form method="POST" name="informati on"...