if you are talking about symantec endpoint 11.0 , it does not require any license or slf file to be added. its just a paper license, if its experied, you need to get it renewed from the licensing team, thats it..this is for your reference only.
Does Symantec Endpoint Protection 11.0 require a license file?
http://www.symantec.com/business/support/index?page=content&id=TECH103025
For Symantec Endpoint Protection 11.0, you are only renewing the maintenance contract. For renewal, you may contact your reseller to renew or contact sales team at 1-800-745-6054 option 3.
- For the registration please contact Customer Care at 1-800-721-3934 option 2 for assistance