Create Fiori Application with multiple entitysets

Hi,

We are developing Custom Fiori Application to create quotation which has header and line item details.

We have two entity sets, QuoteHeader and QuoteItems. Right now we are facing three challenges.

1. From custom ui5 application, how to submit details related to both QuoteHeader and QuoteItems at the same time.

Is there way we can test it from Gateway client to submit the data to QuoteHeader and QuoteItems?

/sap/opu/odata/sap/zgw_create_quotation_srv/???

2. When we generated two entity sets in gateway, it has generated services to support CRUD operations.

But when we see Create service it only supports creation of single record as it is created after structure but not the table.

for eg: er_entity is declared of type zcl_zgw_create_quotati_mpc=>TS_QuoteItems.

How to make/enable Create service take multiple records and update to the database?

3.And also here, we would need single header record and multiple line items from input and save it to database.

So we need a method in the class that need to read both header and item records.

Thanks,
Suraj Pabbathi