Oracle secure backup and worm cartridge

 Hi all,

I am trying to copy a backupset to a worm cartridge with OSB(Oracle Secure Backup Release  10.4.0.1.0)

the scripts is 

 run {

 ALLOCATE CHANNEL c1 DEVICE TYPE sbt

 PARMS 'SBT_LIBRARY=/usr/local/oracle/backup/lib/libobk.so ENV=(OB_MEDIA_FAMILY=CTR)';

 BACKUP BACKUPSET completed between "TO_DATE('09-SEP-2012 01:00:00', 'DD-MON-YYYY HH24:MI:SS')" AND "TO_DATE('09-SEP-2012 08:00:00', 'DD-MON-YYYY HH24:MI:SS')";

  release channel c1;

 }

it works well with normal cartridge but with worm (write once read many) it fails, the device goes in  "AUTO NOT IN SERVICE"

log:

   Not in service reason          Oracle Secure Backup encountered a problem while trying to run