Hi Alexander Sun,
Currently this can not be done out of the box. The only way to achieve that as of now is to place the [Include] attribute above each of the referenced fields you want to be included. When you do that you will simply need to rebuild and our Metadata Provider will pick up everything and generate the corresponding attributes on the client side thus enabling the eager loading. Unfortunately currently we don't have examples showing those features since our RIA support is still a new feature but we are actively working on providing better documentation and example coverage.
the Telerik team
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