Spanish Only Please take a look at the following document created by Marcos Crispino. CreateGXextensionFromScratch
Japanese Version Check the Japanese translation by Yamazaki Keysuke (yamazaki at simplificasoftware.com) CreateGXextensionFromScratch Japanese version
GXextension and GXserver If the extension has logic to be executed in GXserver make sure it was compiled using the following attributes (AssemblyInfo.cs file):
[assembly: Package(typeof(Package), IsCore = false, IsUIPackage = false)]