Wpf – Making the ToolBar Button Style apply to UserControls in the Toolbar

How do I force UserControls in WPF that are inside a ToolBar to use the ToolBar's default button style?

I have a simple user control called ImageButton which has XAML something like this:

<UserControl x:Class="myNameSpace.ImageButtonUserControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Name="imageButton"
    >
    <Button Style="{Binding ElementName=imageButton, Path=ButtonStyle}">
        <StackPanel Orientation="Horizontal">
            <Image Source="{Binding ElementName=imageButton, Path=ImageSource}"
                   VerticalAlignment="Center" 
                   />
            <TextBlock Text="{Binding ElementName=imageButton, Path=Text}" 
                       Style="{Binding ElementName=imageButton, Path=TextStyle}"
                       VerticalAlignment="Center"
                       />
        </StackPanel>
    </Button>
</UserControl>

I have some dependency properties in the code behind for those binding paths and everything works fine.

That is until I put it in a ToolBar. Normally when you put buttons in a ToolBar they are restyled by the ToolBar to look like toolbar buttons. I've found out how I can change this style (see ToolBar.ButtonStyleKey. But how can I apply the already defined style to my User Control's Button Style dependency property?