怎么应用Silverlight ToolKit自带的主题样式到ChildWindow页面下

如何应用Silverlight ToolKit自带的主题样式到ChildWindow页面上
Silverlight ToolKit 4有些自带的主题，就是它的例子中Theme Browser看到的，dll文件在
C:\Program Files\Microsoft SDKs\Silverlight\v4.0\Toolkit\Apr10\Themes\System.Windows.Controls.Theming.TwilightBlue.dll
下面，我看了下例子，如果要运用这个样式只需要在 控件前面包裹
xmlns:twilightblue="clrnamespace:System.Windows.Controls.Theming;assembly=System.Windows.Controls.Theming.TwilightBle"

<twilightblue:TwilightBlueTheme>.........</twilightblue:TwilightBlueTheme>

就可以了。但我想我的ChildWindow的页眉也能应用到他自带的样式，（在Theme Browser中可以看到）

问下我应该怎么写呢

XML code

    <controls:ChildWindow x:Class="AssetsManagementDemo.Views.Base.ErrorWindow"                       xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"                       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"                       xmlns:systemcolors="clr-namespace:System.Windows.Controls.Theming;assembly=System.Windows.Controls.Theming.SystemColors"                      xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"  Title="错误">            <Grid x:Name="LayoutRoot" Width="540">        <Grid.RowDefinitions>            <RowDefinition Height="Auto"/>            <RowDefinition Height="Auto"/>            <RowDefinition/>            <RowDefinition Height="Auto"/>        </Grid.RowDefinitions>        <TextBlock x:Name="IntroductoryText" Grid.Row="0" Margin="0" Text="发生了未知错误。有关详细信息，请与您的管理员联系。"/>        <StackPanel x:Name="ContentStackPanel" Grid.Row="2" Margin="0,6,0,0">            <TextBlock x:Name="LabelText" TextWrapping="Wrap" Margin="0,0,0,2" Text="错误详细信息"/>            <TextBox x:Name="ErrorTextBox" Height="90" TextWrapping="Wrap" IsReadOnly="True" VerticalScrollBarVisibility="Auto"/>        </StackPanel>        <Button x:Name="OKButton" Grid.Row="3" Click="OKButton_Click" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,10,0,0" TabIndex="0" Content="确定"/>    </Grid>        </controls:ChildWindow>