Wpf, How to find Element name from one user control in another - wpf

Question

<TextBox x:Name="DescriptionTextBox"
Text="{Binding SelectedEntity.Description,
ValidatesOnExceptions=True}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus" SourceName="DescriptionTextBox">
<ei:CallMethodAction MethodName="RaiseCanExecuteChanged"
TargetObject="{Binding Command, ElementName=SaveButton}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<userControls:SaveCloseUserControl />
Inside this user control
<StackPanel HorizontalAlignment="Right" Orientation="Horizontal">
<Button Width="50"
Command="{Binding SaveCommand}"
Content="Save" />
<Button Width="50"
Command="{Binding CloseCommand}"
Content="Close" />
</StackPanel>
The problem here is that this TargetObject="{Binding Command, ElementName=SaveButton}" does not find SaveButton because its inside of userControls:SaveCloseUserControl
I looked online and I found a solution (from 2009) that required code behind, is there not an easy way of doing this stuff today?
Regards
Edit
Based on #huzle answer I did this in the code behind of the user control
public object CreateButton { get { return CreateChild; } }
and in xaml i added a name to the save button.
so the my final version looks like this
<TextBox x:Name="DescriptionTextBox"
Text="{Binding SelectedEntity.Description,
ValidatesOnExceptions=True}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus" SourceName="DescriptionTextBox">
<ei:CallMethodAction MethodName="RaiseCanExecuteChanged"
TargetObject="{Binding CreateButton.Command,ElementName=MySaveCloseUserControl}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<userControls:SaveCloseUserControl x:Name="MySaveCloseUserControl"/>

Answer 1

Give your "SaveCloseUserControl" a public properties for the "SaveButton" named "InnerSaveButton" and bind with ElementName to your SaveCloseUserControl and use the Path for getting to the Command of your inner button.
<TextBox x:Name="DescriptionTextBox"
Text="{Binding SelectedEntity.Description,
ValidatesOnExceptions=True}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus" SourceName="DescriptionTextBox">
<ei:CallMethodAction MethodName="RaiseCanExecuteChanged"
TargetObject="{Binding InnerSaveButton.Command, ElementName=MySaveCloseUserControl}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<userControls:SaveCloseUserControl X:Name="MySaveCloseUserControl"/>