How to find the retention of backup in SLP

Hi All

Recently I have taken a full backup in  a disk and duplicated it to tape through SLP with a retention of 2 yrs. While checking the retention level with bpimagelist, it shows the retention of a primary copy not the duplicated copy.

Anyone has any idea how to check the retention of image for the duplicated copy via command.

Netbackup Master : 7.1.02

OS : Solaris 10

Thanks in Advance