AxisTitle not completely visible anymore after rotating

I try to rotate the axistitle on a chart. the title is outside the bounds of the control. How can I make the surface resize to include the axistitle?

I set it in code behind when creating an y-axis. Thats necessary because I cannot style via datatemplates when I bind an axiscollection:

My code for the axis:

            Style s = new Style(typeof(AxisTitle));
            s.Setters.Add(new Setter(NumericAxis.RenderTransformProperty, new RotateTransform(90)));
            s.Setters.Add(new Setter(NumericAxis.RenderTransformOriginProperty, new Point(1, 0.5)));

            yAxis.TitleStyle = s;

In general it works but looks like in the picture.