You should still use the approach where you manually write your code calling the remote services. The datasource components provided out-of-the-box with OpenAccess (the OpenAccessDataSource and OpenAccessLinqDataSource) are only intended to work against a certain database server with connection string and model provided.
What you can use to speed-up your development is the Add OpenAccess service or OpenAccess Ria Service wizards which can generate the service-layer for you. Calling that layer though from the client-side should be accomplished with manual code, which could be written in the Select/DeleteUpdate methods for an ObjectDataSource as an example.
All the best,
the Telerik team
Follow @OpenAccessORM Twitter channel to be the first one to get the latest updates on new releases, tips and tricks and sneak peeks at our product labs!