I´ve searched for hours to find a solution to get PDF invoices automatically after a payment has been done using s2member. Your Plugin looks really great and it´s the best I found I think.
This is what I like to do (and many others from different counties, too - like I read in a lot of forums):
1. Selling a file/service/content/item on a website - s2member looked like the best solution for this http://www.s2member.com
2. After the customer made a payment (e.g. on PalPal) an invoice will be generated automatically and send to the customer by email
3. Maybe print this PDF (on WP-Admin) and send the invoice by mail (in some countries electronic invoices are not excepted by tax burrow)
Yes, that´s what I thought before I did my research... ;-)
So my dream come true would be not to setup the invoice in WP-Invoice - just the template for this of cause and the PDF is being emailed after a purchase.
If IPN is set up to call a script on WP-Invoice and WP-Invoice could get the data from s2member this really would be an award winning solution.
I´m not really familiar with PHP but maybe you could make this dream come true. Please let me know if this is possible and I´ll be the first to buy the WP-Invoice Pro with this feature.