Checkout with Marketpress and Chained Paypal only shows mainsite header

I have a multisite install with Marketpress and I am using the Chained Paypal option for my subsites to checkout. When the user gets to the paypal checkout screen they only see the mainsite header and are told after they checkout that they will be returned to the mainsite when in fact they are returned to the subsite. I want the user to be shown a paypal header that matches the subsite and info that will take them back to the subsite. I am losing sales because buyers get to the payment screen and it looks like a different site.

The main site is webonmission.com. A couple of subsites include grounds2give.com or dancedressconsignement.com. I have attached a screenshot that shows the header banner image with logos from my subsites as this was my work around to show the user that they are still tied to the right place to check out. My new problem is that I am out of space in the header. I have new stores and no where to add their logo.

Ultimately I want the header on the checkout page to reflect the subsite not the mainsite.