Reduced Idoc and conversion rule - input error

Hi all,

I have create a reduced idoc ZCREMAS, based on CREMAS with segment  E1LFA1M (tcode BD53). Then, in BD62, I create a conversion rule for this segment. And in BD79, I create a custom rule (function CONVERSION_EXIT_ZVEND_INPUT) to change the field LIFNR.

But by debug, I have seen that the input value is W9CCS instead of my vendor 42078

Can someone help me to solve this error ?

Best regard.

Marie.