paypal custom checkout fields

I need help with custom fields in paypal if it is even possible. I need to create checkout for site where you buy certain service and when buying that service it is required to provide url of your facebook fan page or twitter page. So my question is how to make something like that happen with paypal checkout. here is the link of the page LINK so basicly what i want is when you click buy now button to somehow integrate in paypal checkout that required field. website is designed in wordpress.

thanks

 

You can only have one custom field on Paypal.
In addition to that custom field you can have some extra fields for reference number and Invoice explatation. If those fields are sufficient for you, then yes PayPal integration can be performed for your page.

 

You can copy the code from here it works http://followerservicesites.com/demos/twitter_followers/