Consuming External OData services from SAP

Hi All,

I am trying to sync up SAP to an external system. Using the SAP Netweaver Gateway I am able to expose the SAP Objects as OData service so that the external system can sync with SAP data.

Now when SAP needs to consume the OData services of the external system can it do through Netweaver gateway ?

How do we build a bi-directional interface keeping both the systems in sync.

Thanks

Ravijeet