To qualify for a non-resident CWP you must own real estate of at least 1/4% in SC. If you do you need to have Form R-168 filled out by the county assessor of the county the property is located in. You can have this done before or after class, it just needs to be done before you have your paperwork in. 

If you are living in SC going to school or for work, etc. You'll need to have your drivers license changed to the SC DL and this provides proof of residency. If you're living in SC for whatever reason and don't want to get the SC DL and don't own land, there's no other way to get the permit outside of owning land, or having the SC DL at this time.