Script problem with growisofs

[Klaas-Henning Mueller <k-hm@gmx.de>]

There's a script-problem with growisofs which makes it nearly impossible 
to use for automated backup purposes:

if you invoke growisofs at commandline or from an script directly with 
"-Z" option, all ist fine, it works great.
But if you invoke it from "cron" directly or in a script, the "-Z" 
option causes growisofs to exit without anything beeing written to DVD
+RW nor erasing it.
If you invoke growisofs in the same way with "-M", all runs fine, but 
the media is not erased before writing.

I guess it's a tty problem ...
Is there a solution for that?

CU
k-hm