Hi all, I'be been at this for days and i cant seem to figure it out. All i want to do is when subscribe button is pushed, a variable is send ( post get i dont care ) payment is completed and landed on the success page, with my variable!

From what i can gather this should be able to do it:

<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="hosted_button_id" value="0000000">
<Input type="hidden" name="custom" value="<?php md5($code.microtime()); ?>"/>
<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>

Any help much appreciated ( and yes I've read paypal and sandbox documentation, just not that good at reading. )