Step export, additional coordinate systems for DIN4003

Hi everybody.

My goal is to make a valid DIN4003 step export of a milling tool.
The tool exists of one compound which holds 2 solid for CUT and NOCUT layers.
I implemented this via the TopoDS_Shape classes.
Both TopoDS_Shape and the step output works fine.

But to make it DIN4003 compliant i need to include some additional coordinate systems per compound.
Something like "Mounting Coordinate System" (MCS).
(The MCS is the reference point of the tool which gets mounted on a holder.)
It should be linked to the compound.
The coordinate system is represented by a AXIS2_PLACEMENT_3 entity

Here are my questions

1. How can i implement such a coordinate system and link it to the compound ?
2. How can i create Layers on which these coordinate systems ar placed on

Here the code which should be the final result.
I need to create the entity #1370 and #512 (I created those manually)

#512 = PRESENTATION_LAYER_ASSIGNMENT('Layer 66','visible',(#1370));

#1423=SHAPE_REPRESENTATION('',(#1422,...,#1370),#1408);
    #1422=AXIS2_PLACEMENT_3D('',#1419,#1420,#1421);
        #1419=CARTESIAN_POINT('',(0.E0,0.E0,0.E0));
        #1420=DIRECTION('',(0.E0,0.E0,1.E0));
        #1421=DIRECTION('',(1.E0,0.E0,0.E0));
    #1370=AXIS2_PLACEMENT_3D('MCS',#1367,#1368,#1369);
        #1367=CARTESIAN_POINT('',(0.E0,-4.2E1,0.E0));
        #1368=DIRECTION('',(0.E0,-1.E0,0.E0));
        #1369=DIRECTION('',(1.E0,0.E0,0.E0));

    #1408=(GEOMETRIC_REPRESENTATION_CONTEXT(3)...

Many thanks for your help