overwrite backup don't overwrite the backup device

I created a plan for a backup. This first truncates the log and after backups the data with overwrite mode and after backups the transaction log with overwrite mode.
The process is using different backup devices for the data and log backups.
The first 2 step is success (truncate and data backup) but in the last step the backup process don't overwrite the backup device. Why ?It had been set to Full databases, after i set to specified database...it was success.
So if I'm setting to full databases, it's can't overwrite the log backup device (only append)...
sneaky |||

Hi Molnarcs,

Just FYI

The backup device can be overwritten even when doing the log backups.

Jag

|||when the backup was set to full databases then in the form the mode was overwrite but if i checked the sql statement (plan's history log- view T-SQL)...in the script was the "backup log model... NOINIT...backup log db_log....NOINIT"...
after when i set to specified database and i choose the db in the script was "backup log db_log INIT" so it didn't have inconsistency between the form and the ran sql script.
(sorry my english)|||

Hi Molnarcs,

you r right you have to secify INIT option with backup log.

Jag