Diagnosis
You can only copy a material list for packaging materials that aredefined as an equipment package. This is not the case for the selectedpackaging material.

Procedure
You can use transaction /ISDFPS/MPO to create equipment packages as"material packages" with type "equipment package".
When you enter the material number of an equipment package as thepackaging material of a handling unit, the materials of its materialitems are proposed for packaging in the number specified there.