Brushes and window/viewport transformations

I'm trying to use different brush fill style patterns in combination with a QPainter instance for which a window and viewport transformation has been set. Now, when drawing rectangles for example, the problem is that the brush patterns end up being scaled up so much that the whole pattern is lost. Is this scaling to be expected, or am I doing something wrong? Also, is it possible to use pattern brushes when a viewport/window transformation is set such that the pattern is drawn correct?

For future reference: I found that Qt should support resizable brush pattern from 4.0 and up. As it turns out, not all platforms are supported yet though.