Welcome to Auctiva, and thanks for contributing to our forum.
Although we do not offer a feature set that is specifically designed for this purpose, we do have a couple options available that may help you record your item ID numbers and shipping locations.
First of all, there is an “Add a Note” button in the “Actions” column next to each item on the Listings pages (Active, Saved and Closed) within your account which you can use to add notes to your listings which will only be visible through your Auctiva account.
We also offer an Inventory management feature, which may be a good option for you if you regularly sell from stock and want to track and list based on these numbers. You can learn more about this option on the following page of our FAQ: http://www.auctiva.com/help/faq/inventory/
If you were to use the Inventory option, an indicator will be displayed next to each item on the Listings pages within your account which tells you the unique product ID assigned to the product in your inventory and, among other things, the number you have left in stock.
As you noticed, we also offer the option to create folders for certain types of data, such as Listings, Inventory items and Transactions. Although folders may present a good way to separate your items based on shipping location, I don't believe they would allow you to effectively organize your items by product ID because doing so would require creating a separate folder for each product.
If you were to create a transactions folder, for example, you would be able to place items on your Transactions page into that folder. On the other hand, if you were to create an Inventory folder, you would be able to place inventory items (such as those available when you mouse over the “eBay Sales” tab and select “Manage” under “Inventory”) in that folder.
I hope this helps clear things up a bit. I see that you have already opened a support case on this topic so, if you need any more specific assistance with this, please feel free to follow up with our Customer Support team directly through that case and we will be happy to continue working with you.