Face-me objects & reflection

Hello,

I have created a scene with a windows and 2D face-me (billboard) tree in front of the window.
I have defined reflection layer for window.

When I start rendering from particular angle, the tree itself is rendered correctly (it faces me), however its reflection in window is deformed and appears as only a thin line.

Is there any setting in VRay or any workaround?

Thank you
Mike