PDMW, manage non SW files?

[LENEW]

I tried to manage autoCAD dwg files by PDMW. The associations I added seem to be unreasonable (reverse of SW concepts). For example, I check the top assembly drawing (DWG) in first, then check part drawing (DWG) and add association simutaneously. The part drawing did list under the assembly drawing, showing an association line. However the top assembly drawing did not show its references in reference tab. Reversly, the part drawing was shown in 'Where USed' tab.

Anybody has this problem?