How to set the dev express toolbar background style wpf

Here is my xaml, the background properties are not rendered for any devexpress control. How to override the inbuilt properties.

      <dxb:ToolBarControl ShowBackground="False" Grid.Row="0"  HorizontalAlignment="Stretch" 
                        VerticalAlignment="Top"
                        AllowCustomizationMenu="True" 
                        BarItemDisplayMode="ContentAndGlyph" UseWholeRow="True" 
                        AllowHide="False" AllowQuickCustomization="False" RotateWhenVertical="False">
        <dxb:ToolBarControl.Background>
            <LinearGradientBrush EndPoint="1,1"  StartPoint="0,0">
                <GradientStop Color="#a9546a" Offset="0.1" />
                <GradientStop Color="#b4506d" Offset="0.2" />
                <GradientStop Color="#9e3763" Offset="0.3" />
                <GradientStop Color="#ac4362" Offset="0.5" />
                <GradientStop Color="#8a3470" Offset="0.75" />
                <GradientStop Color="#753c83" Offset="1.0" />
            </LinearGradientBrush>
        </dxb:ToolBarControl.Background>
     </dxb:ToolBarControl>

To change ToolBarControl's background, override the BarControlThemeKey ResourceKey=BarTemplate resource.

xmlns:dxbt="http://schemas.devexpress.com/winfx/2008/xaml/bars/themekeys"
...
<Window.Resources>
    <ControlTemplate x:Key="{dxbt:BarControlThemeKey ResourceKey=BarTemplate, IsThemeIndependent=True}" TargetType="{x:Type ContentControl}">
        <Border x:Name="Background" Background="Red">
            <ContentPresenter/>
        </Border>
    </ControlTemplate>
</Window.Resources>

To learn more about customizing DevExpress resources, please refer to How to find and change an inner DevExpress control template