How to "Create an empty service"??

The NetWeaver documentation refers to the possibility of developing services (see http://help.sap.com/saphelp_webas630/helpdata/en/14/8e633e0084e946e10000000a114084/content.htm).

For example, it describes how we can create an empty service. The problem is that the examples have dependencies on ApplicationServiceFrame and a number of other core classes and interfaces from com.sap.engine.frame.* . I could not locate the DCs in which these classes and interfaces reside so I cannot define them as Used DCs.

Also, I cannot find an exemple on how to access the com.sap.engine.frame.ServiceContext instance.

Anybody know anything about this and is there more detailed info, documentation, examples on developing J2E services? More specifically, I am interested in accessing the Timeout service.