Printing rotated text to a printer

I have an app that displays data in a spreadsheet format with each column labelled vertically. Works well. However, I now need to produce a printed output. It needs to be more than just a screen dump. So far I create an Image of the same size as the screen then draw all the relevant data onto it. However when I try to write the column headers vertically, they all come out written in horizontal text. The code I am using is a function inside a class:

void PaintView( CGRect rect, NSFont ft)
{
NSStringAttributes attr = new NSStringAttributes(){Font = ft, ForegroundColor = NSColor.Black};
FrameRotation = 90;

((NSString)HeaderName).DrawInRect(rect, attr);

}

called:

rc.PaintView(rect, attr);

What am I missing?

Neil