ugh one more thing! How do I add hidden input to paypal.??

Hey guys, thanks to everyone who's been such a big help. I need one last thing before I can put my stores live. How can I add a single paypal input that gets sent to paypal? Just like the options and such get sent to paypal, i need to send a hidden variable to paypal, just one!

Thanks in advance!!

you mean something that means something to paypal ? sending random inputs won't do anything unless it is known by them

I'm thinking something like the options. You know how the options show up in the paypal invoice? I'd like to do that as a hidden input for internal purposes.