Help tracking affiliate links

Hi,

a client would like to have affiliates linking to his website. The problem is he doesn’t have a store, instead the customers fill out an inquiry form. Then he uses a third party solution for offers, invoicing etc.

Is there anything that can be done in such a setup, something like tracking form submissions and then later manually confirming a sale?

For the record, I do not have any experience in affiliate marketing, and I know this is an awkward setup, but I’d love to know if something can be done – there’s loads of sites with only Enquiry buttons, some of them must be using affiliates…