It would be more than a replacement of a simple form. Use the whole page (Javascript, CSS, etc.). See: https://wyday.com/limelm/help/how-to-generate-product-keys-after-order/
I'm currently using a PayPal "hosted" button to call the PayPal payment screen as follows:
<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post" target="_top"><input type="hidden" name="cmd" value="_s-xclick"><input type="hidden" name="hosted_button_id" value="W24EVN9XL9M36"><input type="image" src="https://www.sandbox.paypal.com/en_US/i/btn/btn_subscribeCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!"><img alt="" border="0" src="https://www.sandbox.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"></form>
What would the replacement <form> code look like to call the payment.php file from the LimeLM Web API Pack?
It would be more than a replacement of a simple form. Use the whole page (Javascript, CSS, etc.). See: https://wyday.com/limelm/help/how-to-generate-product-keys-after-order/
So, I basically got it working by creating a link on my page to the payment.php file. This issue can be closed now.