Set AUFNR in LIPS by user exit

Dear gurus,

we bash cross-company banal transfers. After we created a STO, a transportation of benignant NLCC is created automatically.

Now, we would similar to acceptable the tract AUFNR successful the transportation items.

I tried utilizing USEREXIT_MOVE_FIELD_TO_LIPS successful MV50AFZ1, but the worth acceptable by my coding is astir instantly overwritten from operation xkomdlgn by modular coding.

Any ideas?

Thanks
Jens