I am trying to use WpfToolkit DataGrid in Windows Phone 7 project (Silverligt 4) and it's not working. Here is the XAML:

<UserControl x:Class="SilverlightControls.Grid"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    xmlns:wtk="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"
    d:DesignHeight="480" d:DesignWidth="480">

    <Grid x:Name="LayoutRoot" Background="#FF1F1F1F" Width="960">
        <Grid x:Name="TitleGrid">
            <TextBlock Text="{Binding Title}" Style="{StaticResource PhoneTextPageTitle2Style}"/>
        </Grid>
        <wtk:DataGrid>
        </wtk:DataGrid>
    </Grid>
</UserControl>

The project compiles fine but crashes at runtime trying to load this control. The best clue I got so far is from Visual Studio Designer. Once I add wtk:DataGrid to the control the visual designer does not load and below is the exception it displays.

Could it be that WpfToolkit relies on PresentationFramework.dll and it's not available in SL4?

System.Reflection.Adds.UnresolvedAssemblyException
Type universe cannot resolve assembly: PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35.
   at System.Reflection.Adds.AssemblyProxy.GetResolvedAssembly()
   at System.Reflection.Adds.AssemblyProxy.get_FullName()
   at Microsoft.Windows.Design.Metadata.ReflectionMetadataContext.PrepareAttributes(Reflectable`1 reflectableAssembly)
   at Microsoft.Windows.Design.Metadata.ReflectionMetadataContext.PrepareAttributes(Reflectable`1 reflectableType)
   at MS.Internal.Metadata.ClrType.GetAttributes[T](ReflectionMetadataContext context, IReflectable`1 member, ITypeMetadata attributeType, Boolean merge, AttributeMergeCache& cache)
   at MS.Internal.Metadata.ClrMember`1.GetLocalAttributes(ITypeMetadata attributeType)
   at MS.Internal.Design.Metadata.Xaml.XamlType.GetSpecialProperty(Int32 idx, PropertyIdentifier pid)
   at MS.Internal.Design.Metadata.Xaml.XamlType.get_ContentProperty()
   at Microsoft.Windows.Design.Metadata.Xaml.XamlExtensionImplementations.GetContentProperty(ITypeMetadata sourceType)
   at Microsoft.Windows.Design.Metadata.Xaml.XamlExtensions.GetContentProperty(ITypeMetadata source)
   at MS.Internal.Design.Metadata.ReflectionTypeNode.get_ContentProperty()
   at MS.Internal.Design.Markup.XmlElement.CalcChildWhitespaceImportant(XamlElement element)
   at MS.Internal.Design.Markup.XmlElement.ConvertChildrenToXaml(XamlElement result, PrefixScope scope, IParseContext context, IMarkupSourceProvider provider, Boolean childrenAsString)
   at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider)
   at MS.Internal.Design.Markup.XmlElement.ConvertChildrenToXaml(XamlElement result, PrefixScope scope, IParseContext context, IMarkupSourceProvider provider, Boolean childrenAsString)
   at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider)
   at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.ParseElementFromSkeleton(XamlParseContext context, SkeletonNode node, XamlElement parent, Boolean fullElement)
   at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.UpdateSkeleton(IDamageListener listener)
   at Microsoft.Windows.Design.DocumentModel.Trees.MarkupDocumentTreeManager.Update()
   at Microsoft.Windows.Design.DocumentModel.MarkupProducer.Update()
   at Microsoft.Windows.Design.DocumentModel.MarkupProducer.HandleMessage(DocumentTreeCoordinator sender, MessageKey key, MessageArguments args)
   at Microsoft.Windows.Design.DocumentModel.MarkupProducer.Microsoft.Windows.Design.DocumentModel.IDocumentTreeConsumer.HandleMessage(DocumentTreeCoordinator sender, MessageKey key, MessageArguments args)
   at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.SendMessage[T](MessageKey`1 key, T args, Boolean isPrivateMessage)
   at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.QueuedMessage`1.Microsoft.Windows.Design.DocumentModel.IQueuedMessage.Invoke()
   at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.ProcessQueuedMessages(Object state)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)