Why is the Pen tool the only one that can draw within a mask, unlike the Pencil and Brush tools?

I can’t find a way to use the Pencil and Brush tools within an existing mask. The new layers are not placed within it, even if it’s selected, or if a layer within it is selected.
The Pen tool behaves differently, behaving like you would expect.

1) Is there a way?
2) If there isn’t, please consider this a feature request :p 

Thanks.