JavaFX 2.0 :: Image Overlay Rotation Interpolation Error

I'd like to draw an overlay on an image. The overlay is also an image with a black background and a white foreground. Now the white pixels should be drawn on the image in red. This is possible with the code I posted below. However, the problem arises when rotating the stencil (overlay). I get some interpolation errors from the rotation on the boundaries. I tried to clip them with setClip(), but this turns the background from transparent to white. How to remove those spots? Or maybe a completely other idea of achieving an overlay on the image? I'm aware of the pixelreader and iterating through the stencils pixels and draw the respective pixels as rectangles on a Canvas' graphicContext. However, this was extremely slow, compared to the code I posted below (although it doesn't work with rotations).

Here I surrounded the errors:
 
The image:
 
The stencil:
 
And here is the code:
 
import javafx.application.Application; 
import javafx.geometry.Insets;
import javafx.scene.*;
import javafx.scene.effect.BlendMode;
import javafx.scene.image.*;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;

[Code] .....