[MacDV] DVD-RW

[Neil Bennett]

Hi,
I've just invested in a new Lacie D2 DVD +/- RW Dual Layer Burner, and 
some DVD+RW discs.
I've saved data to a couple of the discs which now needs erasing and 
replacing with new data. How do I erase the DVD+RW's so that my Mac 
will recognise them as blank discs? I've tried erasing them with the 
Disk Utility application but when the erase process is complete the 
DVD+RW's only revert to read only media.
Thanks
Neil