Problem using VisualTreeHelper.HitTest

[Gotch]

Hi,
I'm using VisualTreeHelper.HitTest in the following situation: I have
a grid, that I use to position a certain number of labels. When the
user clicks on one of these labels they won't be able to receive the
click, because the mouse is dragging another element. So I have to use
VisualTreeHelper with the Callback to see all the elements down there.
It works and I can get the elements in the grid. The problem starts
here: it will return a TextBlock, instead of a label. I don't know
why... probably a label is implemented throug a textblock... who
knows... Anyway I use again VisualTreeHelper to get the parent of this
textblock and it gives a ContentPresenter. If I substitute its
contents with what I want, it will work and everything will be
allright... The problem is that it will work only visually. If I look
through the Children of the grid I will get the usual Labels I put at
the beginning and their content will still be the previous (even if
visually it is not!). I'd like to be able to use directly my labels
instead of these other controls. because after the content is changed
I have to know which Label has changed and query it's position in the
table. Probably I'm doing this in the wrong way. I've tried to put a
event handler on the label, but it doesn't work: the dragged object is
above and doesn't let the Label receive mouse events!

so boring... please help