Validation States on TextBox in Silverlight

So, one of the requirements on the project that I'm working on is that we have a Silverlight TextBox that has to display the error balloon/tooltip. Simple, right? However, this TextBox is actually just displaying data, and the data is entered through a dialog, not directly as text on the screen. Furthermore, to ensure that the user does not attempt to enter the data directly, the TextBox is disabled.

You may know where I'm going with this - my Validation Error tooltip never appears! Why? The default style of a TextBox only shows the tooltip in a focused state! Eventually, I realized this. After looking in the MSDN documentation about TextBox, I was able to get the default style of a TextBox, and I was able to override it's InvalidUnfocused state to do the same as the InvalidFocused state - and it worked!

Now to find a more intuitive way for the user to see that error message without it always being on the screen...