How to bind the foreground color of the RibbonBar header in WPF Ribbon control?

<!--  RibbonBar style  -->
<Style x:Key="Office2013RibbonBarStyle1" TargetType="{x:Type syncfusion:RibbonBar}">
   <Setter Property="FocusVisualStyle" Value="{x:Null}" />
   <Setter Property="FontSize" Value="11.5" />
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="{x:Type syncfusion:RibbonBar}">
            <Grid Margin="1,0,-5,0">
               <Border>
                  <Grid x:Name="barGrid">
                     <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="5" />
                     </Grid.ColumnDefinitions>
                     <Grid.RowDefinitions>
                        <RowDefinition>
                           <RowDefinition.Style>
                              <Style>
                                 <Setter Property="RowDefinition.Height" Value="74"/>
                                    <Style.Triggers>
                                       <Trigger Property="syncfusion:SkinStorage.EnableTouch" Value="True">
                                          <Setter Property="RowDefinition.Height" Value="104"/>
                                       </Trigger>
                                    </Style.Triggers>
                              </Style>
                           </RowDefinition.Style>
                        </RowDefinition>
                        <RowDefinition MinHeight="17" />
                     </Grid.RowDefinitions>
                     <Border Name="PART_RibbonBarBorder" Margin="3,0,3,0">
                        <Border Name="PART_presenterBorder" Grid.Row="0">
                           <ItemsPresenter />
                        </Border>
                     </Border>
 
                     <Border Name="PART_headerBorder" Grid.Row="1">
                        <DockPanel>
                           <syncfusion:RibbonButton Name="PART_DialogLauncherButton" Margin="0,2,0,0" Width="15" 
                                 ToolTipService.ShowOnDisabled="{Binding Path=(ToolTipService.ShowOnDisabled),RelativeSource={RelativeSource TemplatedParent}}" Height="13" 
                                 Command="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=LauncherCommand}" CommandParameter="{Binding RelativeSource={RelativeSource TemplatedParent},
                                 Path=LauncherCommandParameter}"
                                 CommandTarget="{Binding RelativeSource={RelativeSource TemplatedParent},
                                 Path=LauncherCommandTarget}"
                                 DockPanel.Dock="Right"
                                 SizeForm="ExtraSmall"
                                 SmallIcon="{TemplateBinding CollapseImage}"
                                 Style="{StaticResource RibbonBarLauncherButton}" ToolTip="{TemplateBinding LauncherToolTip}"
                                 Visibility="{TemplateBinding IsLauncherButtonVisible, Converter={StaticResource BooleanToVisibilityConverter}}" />
                                            
                           <!-- Binding "RibbonBarBrush" value to the Foreground -->
                           <TextBlock Name="header" Margin="0,0,0,2" 
                                      VerticalAlignment="Center"
                                      Foreground="{Binding RibbonBarBrush}"
                                      Text="{TemplateBinding Header}"
                                      TextAlignment="Center" />
                        </DockPanel>
                     </Border>
                     <Border Grid.RowSpan="2"
                                        Grid.Column="1"
                                        Width="1"
                                        Height="{TemplateBinding Height}"
                                        HorizontalAlignment="Left"
                                        Background="{StaticResource Office2013RibbonbarSeparatorBrush}"
                                        SnapsToDevicePixels="True" />
 
                  </Grid>
               </Border>
            </Grid>
            <ControlTemplate.Triggers>
               <Trigger Property="syncfusion:SkinStorage.EnableTouch" Value="True">
                  <Setter Property="Margin" TargetName="PART_headerBorder" Value="5,0,5,0"/>
               </Trigger>
            </ControlTemplate.Triggers>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
   <Setter Property="ItemsPanel">
      <Setter.Value>
         <ItemsPanelTemplate>
            <syncfusion:GroupPanel PanelState="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type syncfusion:RibbonBar}}, Path=PanelState, Mode=OneWay}" />
         </ItemsPanelTemplate>
      </Setter.Value>
   </Setter>          
</Style>
<Grid>       
   <syncfusion:Ribbon x:Name="ribbon" EnableMoreCommands="True" VerticalAlignment="Top">           
      <syncfusion:RibbonTab Caption="Home" IsChecked="False">
         <syncfusion:RibbonBar Header="RibbonComboBox" Style="{StaticResource Office2013RibbonBarStyle1}">
            <syncfusion:RibbonComboBox Text="Font Size" Width="100" x:Name="syncCombo">
            </syncfusion:RibbonComboBox>
         </syncfusion:RibbonBar>             
      </syncfusion:RibbonTab>
   </syncfusion:Ribbon>     
</Grid>

public class ViewModel    
{
  private SolidColorBrush ribbonbarBrush = new SolidColorBrush(Colors.Green);
  public SolidColorBrush RibbonBarBrush
  {
    get { return ribbonbarBrush; }
    set
    {
      ribbonbarBrush = value;
      OnPropertyChanged("RibbonBarBrush");
    }
  }
  public event PropertyChangedEventHandler PropertyChanged;
  public void OnPropertyChanged(string propertyName)
  {
    if(PropertyChanged != null)
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
  }
}