Expand in linq not loading inner data collections from service.

Question

I am seeing odd behavior with service queries! I am using MVVM pattern for a silverlight 3 app on 3.5 framework and Dataservices 1.5.

The following code eager loads correctly the parent object and the child heirarchy perfectly IF and ONLY IF I am preloading the data. But I would like to fetch a different set of the parent object (and its child heirarchy) on different button clicks. What I am seeing is that on button click, only the parent object is retrieved, and the child heirarchy contains nothing. Any suggestions? Any ideas how to tackle this? Thanks all.

The method:

DataServiceQuery<gis_Region> serviceQuery =
   (DataServiceQuery<gis_Region>)(
       from m1 in dbEntities.gis_Region.Expand("gis_RegionValue/gis_Measure")
       where m1.RegionGuid == new Guid(regionGuid)
       select m1);

serviceQuery.BeginExecute(GetRegionDetailAsyncResult, serviceQuery);

The wired Async Result:

DataServiceQuery<gis_Region> query = (DataServiceQuery<gis_Region>)result.AsyncState;

gis_Region region = query.EndExecute(result).First<gis_Region>();