You have to reinstall the old license server (for ESX 3.x host).
Or create standalone license and load them with VIC (but I think that you loose VMotion and other Enterprise feature in this way).
Andre
**if you found this or any other answer useful please consider allocating points for helpful or correct answers
Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro