pptx->png missing chart and symbols

[Louis . Masters]

I'm running into an issue rendering pptx slides to png images.  For the 
most part, it is working, but two issues are standing out:

1.  My chart disappears in the png.
2.  Certain special characters (alpha, beta) are being rendered as boxes 
(guessing this is a font/Graphics2D issue).

Just looking for any direction on this.  I'm a little lost.  Is it 
Graphics2D; POI; ImageIO?

My code:

           img = new BufferedImage(width, height, BufferedImage.
TYPE_INT_RGB);
           Graphics2D graphics = img.createGraphics();
           graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
RenderingHints.VALUE_ANTIALIAS_ON);
           graphics.setRenderingHint(RenderingHints.KEY_RENDERING, 
RenderingHints.VALUE_RENDER_QUALITY);
           graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION, 
RenderingHints.VALUE_INTERPOLATION_BICUBIC);
           graphics.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, 
RenderingHints.VALUE_FRACTIONALMETRICS_ON);
           graphics.setPaint(Color.white);
           graphics.fill(new Rectangle2D.Float(0, 0, width, height));
           graphics.scale((double)width/pgsize.width, (double
)height/pgsize.height);

           slide.draw(graphics);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write( img, "png", baos );

I'm on POI 3.8 under jdk 1.5.

Thanks,
Lou