Shipstation allows you to import separate SOLD TO information (different than SHIP TO information). This information is NOT passed on to the COMMERCIAL INVOICE in the SOLD TO/IMPORTER section.
I spoke with FedEx Web Services and all ShipStation needs to do is use the tag "CustomsClearanceDetail/ImporterOfRecord" and the Commercial Invoice will be correct (see attachement pg 531).
Currently ShipStation only allows the CONSIGNEE to be the SOLD TO/IMPORTER which is not always the case.
Please add this tag to your software. I've seen other requests for this as well.