Hello,
in this context I also realized the following:
If I create a gateway service with an entity (not linked to an ABAP structure) which contains a date related attribute the ABAP field name is automatically set to internal type 'TIMESTAMP' (as mentioned in original post).
In the next step I create the runtime artifacts just by mapping the GettingEntitySet method to a RFC (in the Service Implementation section of the Service Builder). Assuming the date field in the resulting list of the function module is related to internal type DATE the generated OData service will return an error.
The reason is that in the generated method the value of a DATE field shall be moved to a TIMESTAMP field.
That means that if I create a simple service in that way I also have to change all date attributes (or redefine the DPC class and do a DATE -> TIMESTAMP conversion in the data mapping).
Regards,
Juergen