Looking for a Function Module that would return the list of HU's linked to an ODO in EWM

[Nacasuma]

Hi everyone, 

My client has a requirement to print a packing list before goods issue when the staging is completed for an Outbound Delivery Order. The packing list will be the standard delivery note /SCWM/DLV_NOTE but enhanced and tailored to their needs. However, since it is generated before goods issue, I cannot use ERP tables to get the list of all handling units linked to the delivery document. 

Could you please help me find a function module or any other tool that would return me the list of handling units based on a delivery document? 

Thank you