WPF - change Button controltemplate background when Command.CanExecute is false - wpf

Question

scenario:
When using default implementation of button the below functionality works:
When canExeucte command is true -> the button is enabled and button background is not changed.
When CanExecute command is false -> the button is disabled and background is "grayed".
But When using Button ControlTemplate style and CanExecute is false -> the button is disabled as expected but background is not changed.
How can I change the background of the Control Template button ?
image :
https://onedrive.live.com/redir?resid=3A8F69A0FB413FA4!125&authkey=!ALh_kjfxMMNzhSY&v=3&ithint=photo%2cpng
Control Template:
<!--button-->
<ControlTemplate x:Key="ButtonTemplate" TargetType="{x:Type Button}">
<Border x:Name="border" CornerRadius="0" Background="Green" BorderBrush="#FF06A6F0" BorderThickness="1" Opacity="1" Width="147" Height="50" >
<ContentPresenter x:Name="contentPresenter"
ContentTemplate="{TemplateBinding ContentTemplate}"
Content="{TemplateBinding Content}"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
Margin="{TemplateBinding Padding}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
/>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Opacity" Value="0.8" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="StyleButtonTemplate" TargetType="{x:Type Button}">
<Setter Property="Template" Value="{DynamicResource ButtonTemplate}" />
<Setter Property="FontSize" Value="18pt" />
<Setter Property="Foreground" Value="White" />
<Setter Property="Cursor" Value="Hand" />
<Setter Property="Button.Effect">
<Setter.Value>
<DropShadowEffect Color="Black" Direction="140" ShadowDepth="5" BlurRadius="5" Opacity="0.1" />
</Setter.Value>
</Setter>
</Style>

Answer 1

When you re-template a control, all the visual states should be managed by yourself. In this case the disabled state is ignored. For a simple way using Trigger to change the Background if IsEnabled is false:
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Opacity" Value="0.8" />
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter TargetName="border" Property="Background" Value="Gray"/>
</Trigger>
</ControlTemplate.Triggers>