Read component from bom

Dear all,

i need to read item bom quantity of the bom and fill this value in the char_q of configuration ( refered to STPO-MENGE).

I have already create the following procedure : $SELF.char_q = MDATA $ROOT.char_q  and  assgn it to item bom.

But when run CU50 the char is empty.

What am I doing wrong?

Thanks a lot

Daniele