Create Deep Entity - Custom code

Hi!

Just getting started with OData and NW GW, and as such I'm using a SAP CAL instance of ABAP/BW 7.40 on HANA Trial

I have come so far in my training endeavors that I need to build a function to create new Header and Item data in one call.

I'm trying to follow this blog but in that example the number of items per header are fixed, and I need to be able to create n-numbers of items (just as in BAPI_SALESORDER_CREATEFROMDAT2).

Also, I will define number ranges in NRO and use function "NUMBER_GET_NEXT" in order to increment each new HeaderID.

Any ideas on how to do this?