pre- post command to shrink sql transaction logs

Hi,

Ì`ve a problem, i habe a backupjob to backup the sql logs from a remote sql server, after this i shrink the transaction log files manual with a sql script directly on the sql server. What i want is the backupjob in be2012 should run the shrink job when the log backup is complete.

When i edit the backupjob, i can use the pre and post commands, i define a script with a path and fill into teh pre post commands. it doesn`t work. Maby i must use a specially syntax?

any idea?

Thank you