How to bind a property of external control? - wpf

Question

I've a ToggleButton control that I've inserted in my Grid in this way:
xmlns:LSControls="clr-namespace:LS"
and then:
<LSControls:Favourite />
What I need to do is bind the IsSelected property of each item of ListView, infact I've inserted the control inside a ListView like this:
<ListView x:Name="AllMatches" ItemsSource="{Binding Source={StaticResource GroupedItems}}" SelectionChanged="AllMatches_SelectionChanged">
<ListView.View>
<GridView AllowsColumnReorder="False">
<GridViewColumn>
<GridViewColumn.CellTemplate>
<DataTemplate>
<LSControls:Favourite />
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
this will display the control in eac item of my ListView, but I need to check or uncheck the ToggleButton based on the value of IsSelected, this property is available for each item of AllMatches source.
How can do this?
The structure of the control is like this:
<UserControl.Resources>
<BitmapImage x:Key="Star" UriSource="add-favourite.png" />
<BitmapImage x:Key="StarEmpty" UriSource="add-favourite-empty.png" />
</UserControl.Resources>
<Grid x:Name="LayoutRoot" Background="Transparent">
<ToggleButton Focusable="False" Width="19" Height="19">
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Setter Property="HorizontalContentAlignment" Value="Center"/>
<Setter Property="VerticalContentAlignment" Value="Center"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border>
<ContentPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
RecognizesAccessKey="True"
HorizontalAlignment="Center"/>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding = "{Binding RelativeSource={RelativeSource Mode=Self}, Path=IsChecked}" Value="False" />
<Condition Binding = "{Binding RelativeSource={RelativeSource Mode=Self}, Path=IsEnabled}" Value="True" />
</MultiDataTrigger.Conditions>
<Setter Property="Content">
<Setter.Value>
<Image Source="{StaticResource StarEmpty}"/>
</Setter.Value>
</Setter>
<Setter Property="ToolTip" Value="Add to favourite."/>
</MultiDataTrigger>
<Trigger Property="IsChecked" Value="True">
<Setter Property="Content">
<Setter.Value>
<Image Source="{StaticResource Star}"/>
</Setter.Value>
</Setter>
<Setter Property="ToolTip" Value="Remove from Favourite."/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
</Grid>