Convert file *.asm in file *.obj

[Jobbe®]

Hi!
Escuse me for my bad english.
I must convert a model (*.asm) build with Pro/E in a file *.obj. When i
convert this assembly in *.obj the tree of assembly not conserved. I view
all the part as single part, I view the in sub-assembly created in Pro/E as
single part after the conversion. i ask as i can maintain the tree when i
convert the file.
Thanks