Cannot Start Animation from trigger in controltemplate where target is on parent sibling

I'm facing with this problem,

I defined a custom usercontrol class which contains a controltemplate defined in XAML :

public class Master : Control

{
static Master()
  {
DefaultStyleKeyProperty.OverrideMetadata(typeof(Master),
new FrameworkPropertyMetadata(typeof(Master)));
}
    
public TranslateTransform SignalGridTransform
        {
            get { return (TranslateTransform)GetValue(SignalGridTransformProperty); }
            set { SetValue(SignalGridTransformProperty, value); }
        }

public static readonly DependencyProperty SignalGridTransformProperty =
            DependencyProperty.Register("SignalGridTransform",
            typeof(TranslateTransform),
            typeof(Master),
            null);
    }
}

Now, all I want to do is to start an animation on a target grid at upper (usercontrol sibling) level, if a button -inside- the usercontrol is pressed.

To achieve this I thought to pass the transform element that'll be used to target the property for animation, that's why the attribute SignalGridTransform is defined in class :

<Style TargetType="{x:Type EXOGear:Master}"><Setter Property="Template"><Setter.Value><ControlTemplate TargetType="{x:Type EXOGear:Master}"><StackPanel><StackPanel Margin="10"><ContentPresenter Content="{TemplateBinding ContentFrame}" /><Grid Name="ButtonsGrid" HorizontalAlignment="Right" Width="112" ><Button Background="Transparent" Name="Next" Width="71"  Height="88"><Image Source="arrow-down.png"></Image><Button.Triggers><EventTrigger RoutedEvent="ButtonBase.Click"><EventTrigger.Actions><BeginStoryboard><Storyboard><DoubleAnimation BeginTime="0:0:0" 
Storyboard.Target="{Binding SignalGridTransform, RelativeSource={RelativeSource TemplatedParent}}"
Storyboard.TargetProperty="Y" From="0" To="-800" 
DecelerationRatio="0.0" Duration="00:00:00.500" /><DoubleAnimation BeginTime="0:0:0.500" 
Storyboard.Target="{Binding SignalGridTransform, RelativeSource={RelativeSource TemplatedParent}}"
Storyboard.TargetProperty="Y" From="800" To="0" 
DecelerationRatio="0.5" Duration="00:00:01.00" /></Storyboard></BeginStoryboard></EventTrigger.Actions></EventTrigger></Button.Triggers></Button></Grid></StackPanel></StackPanel></ControlTemplate></Setter.Value></Setter></Style><EXOGear:Master SignalGridTransform="{Binding ElementName=grdTrans }" /><Grid  Name="mainGrid"  HorizontalAlignment="Left" VerticalAlignment="Top" Width="694" Height="1261" ><Grid.RenderTransform ><TransformGroup ><TranslateTransform x:Name="grdTrans"  X="0" Y="0" /></TransformGroup></Grid.RenderTransform><TextBlock>
 This Text Will Scroll</TextBlock></Grid>

The ScaleTransform Element, seems to be correctly passed o the usercontrol via the binding :

Storyboard.Target="{Binding SignalGridTransform, RelativeSource={RelativeSource TemplatedParent}}" Storyboard.TargetProperty="Y" 

but no animation takes place.. Any Explanation for this behaviour ?

Thanks for any help on this, Marco

Marco Orlandi EXO System Italia SRL