1. Uninstall previous versions of ArcGIS, erase any traces too (use CCleaner to clean registry, delete ESRI/ArcGIS folders in Program Files, Appdata, ProgramData, etc)
 2. Install ArcGIS 10.1 without License Manager
 3. Install Pre-Release License Manager
 4. Use Keygen to create license file, set version to 10.1
 5. Replace text in ...\ArcGIS\License10.1\bin\service.txt with generated text
 6. Adjust host and port values as needed in text (change port if running other FlexLM managers!)
 7. Run LSAdmin, reread license file if needed
 8. Run ArcGIS Administrator, check ArcInfo Concurrent License
 9. Set License Manager box to localhost.
 Done!