I've tried it many times, but it seems impossible.
The reason is simple: the remote script checks the Headers
so you can't send data from another server.
Robot Fixing Himself

Perfectly reasonable, makes sense and blocks loads of spam attempts.
However it does make my life harder to make automations for forms.

The situation is of the following:
Say I have a post I want to make in a couple of forums.
If it's the POST sending method there's 99% chance I'm screwed.

Why? Simple, a PHP script that gets data from somewhere and does
something with it (whatever it might be), if it's been made by someone who's not 10
years old, will check to see if the data was sent from the server.

The only way to actually automate this thing is to use a real programming language
that would simulate a browser entering the page and submitting the form.
Quite frankly, that's lame... And so many things could go wrong with it.

I guess the robot can't fix himself...No idea how does it relate but hey,
it made me draw a robot & try the Xara Vectorizing thingy for the first time)