Generic framework to create different types of invoices in AX 7 by Odata services

Hi,  

My problem is I want to create a generic framework  by which user can create invoices or journals for any dataentities in Dynamics 365 for operations (AX7) using Odata service from client app. These dataentities can be custom created or system.

Currently I can create pending vendor invoices using Odata service from external client app. But that involves some static codes like predefining a VendorInvoice object, populating it  and then calling the context.AddToVendorInvoice(vendinvoiceobject).

But i want to get rid of these stuff and make it generic for all types of custom invoices and journals.

Whats the best way out?