I dont really understand... but this will help i think...
When making a unit, make a EMPTY, OBJECT, and look through the type untill you find H (Invisable). PLace this invisable H where u want the chopper to land. THEN. When making the Choppers "Transport Unload" waypoint, hold down the Shift Button, and double click on the invisable H, if you have waypoints selected, it will open up a new waypoint that is locked to that unit (the invisable H). It wont always land exactly on the H, but it will try. You can also use this method for creating a DESTROY waypoint, simply hold shift, double click onthe unit you want destroyed, and set the waypoint type to destroy....