First, create a subclass of OBCommand. Then you need to implement at least the

methods #execute, #label and #isActive (have a look at eg. OBCmdNewClassTemplate).
Finally, you can add a method called eg. 'cmdAIDATemplate' to OBCodeBrowser or a
subclass of it. It is important that this method starts with 'cmd'. When you then
start a new system browser, the command should be available (if #isActive answers
true for the selected class).