actions to return entity with expanded navigation links

[avestnik]

please consider the following scenarion

public class Parent
{
    int TotalKPI;
    ICollection<Child> Children;
}

public class Child
{
    int KPI;
}

action does some complex business processing (which is not possible to do on client) that results in creating or updating parent and related children. how to return created/updated parent with all related chidren? now I can either return parent with empty .Children or collection of children

[xuubin]

You can use ODataMessageWriter to write the expand entry. What block you from doing this?
Can you provide more detail information here?