Changing "insertion point" cursor in WPF

I need to create a "command line" look-and-feel in a WPF app. In WPF, text boxes use a blinking vertical line as the insertion-point cursor. In the command-line world, the insertion-point cursor is a grey rectangle.

Is there a way to change the look-and-feel of the insertion-point cursor in a WPF text box? The obvious (Cursor="Cursor.Whatever") only changes the look-and-feel of the mouse cursor when you hover over the text box, not the insertion-point one.

I would greatly appreciate any help. Thank y'all so much for your time!

Ria.

From stackoverflow

• You mean "caret". And currently you can't change its shape in WPF. Only color is changeable (its inversion of background; background may be transparent, but caret always will be visible).