Outbound Delivery Handling Unit HU material box pallet

Question

Business requirement.
To create a delivery based on a sales order using a function module. To do this, users have an AbapWebdynpro application to collect data, 
Handling units for boxes and handling units for pallets are creates as the user packs his materials in the application.
Items are packed in boxes and boxes on pallets.
Problem description: cannot pack boxes onto pallets.
I can pack items in boxes no problems. Delivery gets created ok.
How i do it:
Step 1:
At the end of AbapWebdynpro process and validations, if no errors occurs, a function module is called to format the data and call fm to create a delivery.
This part works as expected and is all ok.
Step 2:
Then in the function module that will create de delivery, header proposal is filled for boxes and pallets. itemproposal is filled for items in boxes and pallets
Step 3:
then,
FUNCTION 'BAPI_HU_CREATE' is used to create handling units for items
This part works perfectly for boxes and items but not for pallets.
then, delivery create
CALL FUNCTION 'SD_DELIVERY_UPDATE_PACKING_1'
EXPORTING
delivery = ls_createditems-document_numb
commit = 'X'
synchron = 'X'
TABLES
verko_tab = i_verko
verpo_tab = i_verpo
prot = i_prot
it_handling_units_1 = i_handling_unit
EXCEPTIONS
update_not_possible = 1
OTHERS = 2.
This part works fine also if not pallets HU are present in the data .
The problem is when i want to create a pallet and add the boxes to it. I have tried about every thing i read but had not much success.
The only thing that came close to doing the job is the following code.
First i create the delivery with boxes and materials only and with the following FM, i create the pallet and attach it to the delivery line but then i can not assign the boxes to it.
ls_handling_units-top_hu_external = ls_packed_pallets-hu_pallet.
ls_handling_units-top_hu_internal = ls_hupallet.
ls_handling_units-venum = ls_huboxes.
ls_handling_units-vepos = ls_packed_boxes-posnr.
ls_handling_units-rfbel = lv_vbeln.
ls_handling_units-rfpos = ls_packed_boxes-posnr.
APPEND ls_handling_units TO lt_rehang.
Step 4:
CALL FUNCTION 'SD_DELIVERY_UPDATE_PACKING_1'
EXPORTING
delivery = ls_createditems-document_numb
commit = 'X'
synchron = 'X'
TABLES
verko_tab = i_verko
verpo_tab = i_verpo
prot = i_prot
it_handling_units_1 = i_handling_unit
EXCEPTIONS
update_not_possible = 1
OTHERS = 2.
Is anyone succeed to create a program to create outbound delivery where materials are pack into boxes and those boxes are packed on pallets.
Regards
dstj

Answer 1

If the delivery document PGIed then you need to do VL09 transaction to reverse the PGI document.
Then do in VL02N transaction  select Delete handling unit assignment icon it will remove all the handling units from delivery.
Later goto EDIT option then selct copy pack qty as dlv qty then save.Later system will allow you to delete the document.