[OperationContract(AsyncPattern = true, Action = "http://schemas.microsoft.com/sqlserver/2005/06/30/reporting/reportingservices/SetDataSourceContents", ReplyAction = "*")]
IAsyncResult BeginSetDataSourceContents(SetDataSourceContentsRequest request, AsyncCallback callback, object asyncState)

<OperationContract(AsyncPattern:=True, Action:="http://schemas.microsoft.com/sqlserver/2005/06/30/reporting/reportingservices/SetDataSourceContents", ReplyAction:="*")>
Function BeginSetDataSourceContents(request As SetDataSourceContentsRequest, callback As AsyncCallback, asyncState As Object) As IAsyncResult