>I can put the calculator and diary in menus with _mst_calcu, _mst_diary; but I can't get them to work with sys(1500). What would be the menuname to use in the sys(1500) function, or isn't this possible?

You don't need sys(1500) for that. Directly activate their window (provided using a resource file). ie:

activate window "Calculator"
activate window "Calendar"

Cetin