Printing Direclty to CD/DVD

I recently purchased the canon ip4200 printer for the purpose of printing directly onto cds and dvds.

the canon cd labelling software is very intuitive to use, however i would like to create/edit the images i print in photoshop and would like to be able to visualise the finished results before i am ready to print. to that end i have created a template in photoshop that is the diameter of the printable area on a cd and would like to create circular guides on the template to mark the interior and exterior printing boundaries. does anyone know how to do this.
thanks in advance
Simon

Under View, turn on Rulers and then pick up a guide from the ruler (so click on the ruler, either one) hold the mouse key down and place the guide where you want the edges to be of the CD. You effectively get a guide from click holding on the ruler and moving it into the area that you want it to be then release it. Have a play around with it, you have my business card with my phone number on it if you want to call me about it.