InkCanvas problem

Hi,
I have a question concerning InkCanvas control. Perhaps someone could solve my problem. Namely I’m adding a child to this control and after that want to use eraser. Unfortunately it’s impossible to modify the child element using eraser, however, it’s possible to use ink for this purposes. Of course there’s a workaround to use white ink instead of eraser but I am wondering if it is possible to it the “right way”.

Regards,
Martin