Hi emmabluewho,
Thanks for posting your question here. Since you have opted into eBay's Global Shipping Program and you do not see the option to select it on the Auctiva lister page, I suspect you just need to generate a new eBay token to force our system to recognize that you have enrolled in the program.
You can generate a new eBay token from within your Auctiva account by mousing over the "My Account" tab, selecting the "eBay" option under "Settings", clicking the "Get New Token" link on the ensuing page and then proceeding as directed.
Once you have done so, you should then find the option to choose the Global Shipping Program in the Shipping Tools section of the Auctiva lister page.
If you still do not see this option after generating a new token, please contact our Customer Support team directly from under the "Help" tab within your account and we will be happy to work with you on this further.
-Mike