They do this in the imported S.U.I.T. scopes for the AR and Fn-Fal. Not sure if the tritium/LED replacement insert is standardized for different models (probably not), but you could try DSA Arms to see who makes the LED insert for the SUIT (they still sell the SUIT I believe and may be able to help). Perhaps trijicon could replace the burned out tritium in your scope, even though it isn't their model. LAter.