Hi Arne
I'm not clear on the relationship between material xyz and abc. Is xyz a component of abc?
You say that xyz is made externally. So do you really need this to be an SFC in your system, or can it be an Inventory ID? If it's an SFC, then it will need a routing associated with it, which makes it more complex to handle.
If I also understand correctly, you want the unique number of the xyz material to form the first part of the abc material SFC - is that correct? You do have the possibility to create your shoporder with serial numbers that you supply for example, but you won't be able to get Net Number to use the individual numbers from the xyz material.
Stuart