Havent used blpackage for this
the attribute maxage should be set to 0
u can check in /etc/security/user
You can use the command chuser to set this
Have you tried adding a live server object in your BLPackage, and deploying the user?
It allows you to set many of the different attriibutes for the user -- and the maxage should be set to 0 for never expires.
If you want to check on a user's attributes ... you can user lsuser ... like lsuser -a maxage <user>.
And to set the maxage would be chuser maxage=0 <user>