Hi amethystguy,
Thanks for posting about this. I suspect you are already aware of this but, for the benefit of others that may come across this thread, I'm inclined to clarify that the issue cited here is that eBay will not allow items that are configured to use third party checkout system to combine with items configured to use eBay Checkout.
Since you disabled the "Use Auctiva Secure Checkout" setting in your account, the items you post through Auctiva thereafter will use the eBay Checkout system. However, your items that were already posted through Auctiva while Auctiva Checkout was enabled will continue to be processed through Auctiva Checkout.
As a result, unfortunately, you may continue to have problems combining the items that you already posted through Auctiva while Auctiva Checkout was enabled with items that are configured to use eBay Checkout.
I hope this helps. If you have any other questions, please feel free to contact our customer support team using the form on the following page of our site: http://www.auctiva.com/help/requesthelp.aspx#
-Mike