CD's CD's everywhere but not a signle RW

Okay, downloaded the PCBSD 0.8-alpha ISO onto my Mac mini, It's the one without superdrive so i have a CD-RW/DVD-ROM combo, all my x86 systems have DVD-/+RW drives and one even has a DVD-/+RW +R9 drive, well I have a couple DVD-RW disc's lying around but I can't believe I doin't have a single CD-RW lying around.