B1 Service Layer Get a invoice from a order

Hi everyone!

I have a question about the relationship between Orders and Invoices... In oficial SL documentation i can see about how to know the invoices from a particulary client knowing for example a order....The example is like that:

Orders(1)/BusinessPartner/Invices

The problem is... I need to know the invoice from base order... Something like this...

Orders(1)/Invoice

I dont know how to do that relation... i can see a "BaseEntry" in database, but that value is not in the SL queries

Thanks a lot for your time and support, regards.