I just try to post data to
https://perfectmoney.com/api/step1.asp If no data is received the page redirects to the index page.

And when I try your snippet (Thank you for it :), I get a "302 moved" reply, or a blank page if I run the script in a browser from the browser.

If I embed the data in a html POST form, it works (Even if the data is wrong, I get some error messages from the asp script, that is normal).