Right now, the shipping method is not imported into Volusion. When we used World Ship, we had to map each shipping method to an ID.
Ground Shipping => 502
2nd Day Air => 503
The main issue is that different stores have different shipping method IDs, so every store would need their own conversion. But this is easily solved, because you can export the method ID list with a custom SQL export if someone wanted to automate everything:
There you have a list of all the shipping methods, their volusion IDs, their carrier (Gateway), and the service code used by the carrier. You could also have a manual entry system, so customers could make their own settings.