Hello.

I have some very large objects server-side, some of them upwards of 1Mb due to many fields and multiple variations of images. However, any given view only displays a subset of these fields, for example:

            <ext:Model runat="server" Name="Step_Model" IDProperty="Id">
                <Fields>
                    <ext:ModelField Name="Id" />
                    <ext:ModelField Name="DisplayName" />
                    <ext:ModelField Name="BatchId" />
                    <ext:ModelField Name="Quantity" />
                    <ext:ModelField Name="ImageSource" />
                </Fields>
            </ext:Model>
In these cases I've found that using an `<ext:Sore>` with an `<asp:LinqDataSource>` actually filters the data server-side and passes only exactly those fields to the client, vastly reducing the amount of data transferred:

            <asp:LinqDataSource runat="server" ID="UnassignedSteps_Source" OnSelecting="UnassignedSteps_Selecting" />
            <ext:Store ID="UnassignedSteps_Store" runat="server" ModelName="Step_Model" DataSourceID="UnassignedSteps_Source" />

    protected void UnassignedSteps_Selecting(object sender, LinqDataSourceSelectEventArgs e)
    {
        e.Result = GetAllSteps();
    }
That is, unless the models have associations:

            <ext:Model runat="server" Name="Batch_Model" IDProperty="Id">
                <Fields>
                    <ext:ModelField Name="Id" />
                    <ext:ModelField Name="DisplayName" />
                </Fields>
                <Associations>
                    <ext:HasManyAssociation Model="Step_Model" Name="Steps" AssociationKey="StepIdsReal" />
                </Associations>
            </ext:Model>
With this model, a store with a datasource doesn't load ANY of the associated data. I've tried setting the `StoreConfig` property for the `ext:HasManyAssociation` to point to an existing datasource (this just crashes because the datasource specified doesn't exist in the temporary internal page created for that store). I've tried explicitly specifying foreign and primary keys. The closest I got was the initial data sent from the server contained ALL the data for the sub models, but the page couldn't see or render them.

Ideally, I want to be able to somehow load child data (`Step_Model` in this example) with the same server-side filtering as the parent object (`Batch_Model`) so only three fields for the outer object are sent - `Id`, `DisplayName`, and `Steps`, and within the `Steps` array the objects only contain the fields specified in their model.

Currently the only way I can display all the data is setting `.Data` in `Page_Load`, but that transfers vast amounts of data; plus I have to be very careful with the data that there are no recursive references because it will never resolve. With the `asp:LinqDataSource` method that doesn't matter, because the fields are filtered and unspecified ones are never traversed.

How can this be done? Even some solution involving multiple stores, multiple data sources, and cross-references between them to get the associated data for one model from another store would be amazing. Thank you.