NetBackup 7 - How to display data expiration on a disk image

DOCUMENTATION: What are the different fields in "bpimagelist -l" output?
http://www.symantec.com/business/support/index?page=content&id=TECH5584

You will need field 16 of the IMAGE entry

e.g.

# bpdbm -ctime `bpimagelist -l -backupid client_1316242916|grep IMAGE|awk '{print $16}'`
1318921316 = Tue Oct 18 08:01:56 2011

where the bpimagelist output produces a value of 1318921316 & this is fed into bpdbm to convert to a more readable format.

***EDIT***

To follow that theory through with your example:

# bpdbm -ctime `bpimagelist -l -backupid client_1316694010|grep IMAGE|awk '{print $16}'`
1317298810 = Thu Sep 29 13:20:10 2011
#
# bpexpdate -backupid client_1316694010 -d 12/31/2015 18:00:00
Are you SURE you want to change client_1316694010
to expire on Thu Dec 31 18:00:00 2015 y/n (n)? y
#
# bpdbm -ctime `bpimagelist -l -backupid client_1316694010|grep IMAGE|awk '{print $16}'`
1451584800 = Thu Dec 31 18:00:00 2015

***EDIT #2***

[[As an aside, as you look like you want to view this via command line, this can also be confirmed via the Client Backups report in the GUI - also gives the equivalent output to bpimagelist ]]