WinRT Cascading async Calls

private async void engine_SaveRequested(object sender, SaveRestoreEventArgs e)
        {
            await dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.High, () =>
            {
                //create a Saved Game folder for saving all the games to app local folder or open existing folder
                var savedGameFolder = await ApplicationData.Current.LocalFolder.CreateFolderAsync("SavedGame", CreationCollisionOption.OpenIfExists);
                //set currently saved game folder name
                string gameFolderName = DateTime.Now.ToString("yyyy-MM-dd-hh-mm-ss") + ".save";
                //create folder for currently saved game in the SavedGame folder and append a integer value if file name exists 
                var currentGameFolder = await savedGameFolder.CreateFolderAsync(gameFolderName, CreationCollisionOption.GenerateUniqueName);
                //create currently saved game file in the currentGameFolder with the gameFolderName
                var savedGameFile = await currentGameFolder.CreateFileAsync(gameFolderName, CreationCollisionOption.ReplaceExisting);
                //open savedGameFile stream for writing
                var stream = await savedGameFile.OpenStreamForWriteAsync();
                e.Stream = stream;
            });
        }

The above code does not compile.

I've tried to work through it a number of ways, but a solution escapes me.

The point of the function (called from a non-UI task thread) is to do the steps as a transaction. Each step in order with a result so that e.Stream has a file Stream.

I can do this if I block the UI, but I don't want to block. I want it to just run through the statements as they are...I don't care if each statement is asynchronous as long as they run in order and don't end the engine_SaveRequested method until everything is done.

Help?

Dave