CRE Loaded Community

This is a fresh install of creloaded. I'm Working for a client that requires customers to pay a $15 registration fee before they can buy a product. This is something that could get tacked on at checkout, or elsewhere, but it needs to be charged. The registration lasts for 12 months, after that time, they have to pay the registration fee again to buy more products.

I am familiar with other eCommerce platforms but not creLoaded.

In my head this is what I was picturing--
basically what needs to be coded is two new fields within the database that specifies whether they PAID the registration fee ($15) and what DATE they paid it on. TRUE if they paid it, FALSE if they have not. If they HAVE paid it within the last 12 months, then the system moves on just as it normally would. If they HAVE NOT paid it, then the system prompts them to pay the $15 fee first, or adds it to the shopping cart (even more coding, because if it gets added then it should not be able to be removed, by the rules of the assignment. so it has to get added near the end of checkout).

So does anyone have suggestions on how to proceed with this required registration fee? Thanks in advance for any advice.

Something like this: http://www.oscommerce.com/community/contributions,1658 ?

Simon