AutoCAD Inventor :: Coversion IDW With Linked Bitmaps To DWG And DXF

I am trying to convert idw to dwg and dxf format using InventorAPI (TranslatorAddIn). My test.idw document contains 2 sheets with 2 linked bitmap in titleblock. After conversion I get in my output folder:

2 dxf files for each sheet2 dwg files for each sheet8 bitmap files  (2 for each format and sheet)  The problem is with names of the bitmap files: test1.png, test2.png, ... , test8.png.

It's really hard to say which bitmap is linked to which file. Is the way to handle the naming problem?  

The secand problem is if I convert to dwg and dxf in separete folder I have 2 times bimat numberd from 1 to 4. In that case I have naming colision problem but I cannot simply change name of this bitmap because dxf and dwg files keep the reference to that one.  

Is any simply way to programmaticaly change the reference to linked bitmap in dwg and dxf files?