Hi,
The only current mechanism to save eBay created listings is the Import Listing for Closed listings (normally can use for any Closed in last 90 days, i.e. still viewable at eBay). Note, you can Relist from Auctiva or eBay to keep a Store item listed during a cutover period.
Are you looking to revamp current templates with the Auctiva templates and tags. If so, are there really 800+ unique, or do you repeat listings with just a few variations of a small group of standard templates?
I can see where many are reassessing or revamping on the basis of the new policies and IFRAME design under beta. That is a "challenge".
Do you currently use one of eBay's listing tools (like TurboLister)?
Danno