Btrieve for NW5.1

A recent article shed light on the Pervasicve SQL/btrieve licensing for NW5.1. It seems that if you do a new install, only a 2 user license is installed, while an upgrade of a server gets a time-bombed unlimited license. The article indicated thatyou could install the time-bombed unlimited license optionally but I have not been able to see how or where to do it.
Does anyone know how it is done?