I do not have an answer how it will be through IDocs.
As you have to active click the create batch button in VL31N, I guess this is not supported in the Idoc.
I know from initial inventory load by Idoc and Bapi method that it will not create batch records.
Instead you have to have an extra IDoc for Batch creation which need to be processed before the inventory movements are created. In the movement you then just mention the number.
I could imagine that it is similar in this case, but as initially said, I am not certain.