How to make Entity methods in RIA DomainContext work asynchronously

Intro:

I have a RIA service on Silverlight application that generates the code from the .Web app. On a server side, I am using EF4 and a DomainService based on a EF4 model.

First example:

If I extend the DomainService with my own methods implementing IEnumerable or IQueryable the RIA generates the appropriate methods on its DomainContext class. Something like this:

public partial class SymbolicDataServ开发者_如何转开发ice
{
    public IQueryable<Chemical> GetWeightedChemicals(int min, int max)
    {
        // ... some EF query here
    }
}

RIA generates the method, so I can do something like this on Silverlight side:

private void btnLoad_Click(object sender, RoutedEventArgs e)
{
    SymbolicDataContext db = new SymbolicDataContext();
    var chemicals = db.Load(db.GetWeightedChemicalsQuery(10,24), onChemicalsLoaded, false);
}

and then I respond to the loading in a onChemicalsLoaded callback function.

Second example:

If I want a method that does not return IEnumerable or IQueryable, but is a void method, I mark the DomainService's method with [Invoke] attribute:

[Invoke]
public void FlushChemical(Chemical chemical) 
{ 
    // some code that does what it does (with EF)
}

Now I can do something like:

private void btnLoad_Click(object sender, RoutedEventArgs e)
{
    SymbolicDataContext db = new SymbolicDataContext();
    var chemical = db.GetWeightedChemicals(10,24).FirstOrDefault();
    db.FlushChemical(chemical);
}

Third Example:

If I do:

public void ShakeChemical(Chemical chem, int timeShaking)
{
    // Shake the chemical until it drops
}

RIA will create an Entity method on client side that enables me to do this:

private void btnShake_Click(object sender, RoutedEventArgs e)
{
    Chemical chem = (ListBox)sender.SelectedItem as Chemical;
    chem.ShakeChemical(22);
    db.SaveChanges();
}

Question:

My question here is how to make the last two examples work asynchronously like the LoadOperation? In the first example, I can use callback on Load method to respond to the operation completion, but I have no idea how to make the other two functions asynchronous and I don't want my UI to block during the calls.

EDIT:

I see now that the second example's method has an overload with Action argument so I do have a callback for the second example. However, the question remains for the third example.

I'm assuming that the third scenario is updating a Chemical object in some way?? If this is the case then just look into "Named Update" methods for RIA Services. Hope this helps