Inventory Org not appearing in LOV for Tax Exception setup

Hi, I'm considering using Tax Exceptions to apply tax on a freight item for Canada. The default tax would be exempt on all transactions except for freight items. However, I do not see the Inventory Org I require in the list of values when creating the Tax Exception. I can see other orgs within our company but the the org for our region. Does any one have a suggestion on a setup I may be missing? Thanks.