core_grade_xxx_grades() has itemtype and itemmodule as required parameters, which is kinda issue for me, when I need all grading schemes (grade_items).

Follow http://docs.moodle.org/dev/How_to_contribute_a_web_service_function_to_core

Parameters:
-----------
array of courseids
(suggestion for optional parameters are welcome)

Return value:
-------------

@return list of object (

    object (

        'id',

        'courseid',

        'itemname',

        'itemtype',

        'itemmodule',

        'iteminstance',

        'grademin',

        'grademax',

        'gradepass',

        'aggregationcoef'

 	'locked'

    )

)