I'm trying to migrate the BOM's data with the ECN reference, with an LSMW based on a record of transaction CS02.

The problem is that when I give in input to CS02 the change number and an alternative date for the ECN as valid from the date is automatically re-setted to the ECN's valid from header date.

Is there any way to make the system take the alternative date?

current customizing settings allow Alternative date selection (there's a flag in OS54, "Assign Alternative Dates" that is flagged) but I'm not getting the selection pop up window if I put only the ECN without the date, and honestly I cannot manage this window in a record for an LSMW.

Do you have any suggestion to migrate BOM data with ECN (with the correct Alternative Date Assignment)?

Also I have situation where ECN header date is in past than BOM Header date.

Do you know if there's any way to manage a mass assignment of object to an ECN alternative date?

Thanks a lot guys.