WP8(8.1) How to see static data for LongListSelector in DesignView?

Question

Having some issues adjusting margins properly and having to launch the emulator each time to check it has become a royal pain and inefficient. Ive looked a tutorial that uses blend but I have been unable to see generic data loaded in the longlistselector in Design View. If it helps any, my app loads data into the LongListSelectors from xml files.

Public void LoadData()
 {
   Test = LoadFromXml("Test.xml");

 IsDataLoaded = true;
    }

    private SoundGroup LoadFromXml(string xmlName)
    {
        SaveSoundGroup isolatedGroup = new SaveSoundGroup();
        SaveSoundGroup assetsGroup;
        XmlSerializer serializer = new XmlSerializer(typeof(SaveSoundGroup));

        using (Stream fileStream = Application.GetResourceStream(new Uri("Xmls/" + xmlName, UriKind.Relative)).Stream)
        {
            assetsGroup = (SaveSoundGroup)serializer.Deserialize(fileStream);
        }

Here is a sample of the xml. Items is what is tied to the longlistselector:

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<SaveSoundGroup xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <Items>
        <SoundData>
            <Title>Test</Title>
            <FilePath>https:***</FilePath>
            <SavePath>Test.mp3</SavePath>
            <Status>NotDownloaded</Status>
            <DownloadProgress>0</DownloadProgress>
        </SoundData>

I've tried adding this to my xaml, with no luck:

mc:Ignorable="d"
d:DataContext="{d:DesignInstance IsDesignTimeCreatable=True}"

LongListSelector:

<controls:LongListSelector x:Name="LongList6"
                Margin="0,10,0,0"                        
                ItemsSource="{Binding Test.Items}"
                LayoutMode="Grid"                       
                GridCellSize="400,72"
                ItemTemplate="{StaticResource SoundTileDataTemplate}"
                SelectionChanged="LongListSelector_SelectionChanged"
                IsGroupingEnabled="True"              />
        </controls:PivotItem>

Edit: All I want is for the Tiles in the longlistselector, with some text(Title), to be viewable in design view. Just two tiles even, would be good enough to be able tweak and edit placement and layout.