Jumping through PayPal hoops to get MarketPress chain payments working.

Here are some questions that PayPal wants to know about my setup. I figured you guys would know best how to answer them. Then others users can know what else to add to their applications. I mentioned that MarketPress was already approved and that my site was running the same setup. Please see the questions below.

-Thanks for your submission. Before we approve your application, could you please response back to us for a few questions? 1) Who is the primary receiver and who is secondary receiver in the chained payments? 2) Who is paying PayPal fees? Is it primary receiver or secondary receiver or each receiver? 3) Is your application connecting with sandbox and allow us to run testing to see how PayPal is used in your application? It seems the app is connecting with production environment not sandbox. 4) You mentioned that you have an approved app in the past; can you let us know the name of the application or the App-ID?