Vista - Binding to same DP on another instance of same object won't work.

Hi,

I'm trying to bind the value of a custom control DP to the same DP on
another instance of the same custom control but receive a message
indicating that the "ElementName" is invalid...

Here is an example of the code I use:

<CustomControl1 x:Name="my_custom_1"/>

<CustomControl1 x:Name="my_custom_2
PropOne="{Binding
ElementName=my_custom_1,Path=PropOne,UpdateSourceTrigger=PropertyChanged}"

PropTwo="{Binding
ElementName=my_custom_1,Path=PropTwo,UpdateSourceTrigger=PropertyChanged}"

PropThree="{Binding
ElementName=my_custom_1,Path=PropThree,UpdateSourceTrigger=PropertyChanged}"
/>


This would return me that "my_custom_1" was not found...

In addition, If I substitute the second "CustomControl1" for 3
TextBlock and use the
same binding declarations, eveything works fine...

Any idea?

Thanks

Marcus