How to use Captive Portal With OpenVPN?

[d-ron23]

I have a pfsense box running version 2.1.5. On the box I have an OpenVPN Server running. I want to make it so that I can give people a default config file and when they connect it opens a page where they either sign up or login. I don't know if thats possible but if it is could i be directed to a tut. And also possibly link a paypal page.