Please test this on an experimental zone first.

It looks like you run:

Code:

# zonecfg myzone

and then type in:

Code:

zonecfg:myzone> remove inherit-pkg-dir
zonecfg:myzone:inherit-pkg-dir> set dir=/lib
zonecfg:myzone:inherit-pkg-dir> end
zonecfg:myzone>

Then confiorm what you have asked for:

Code:

zonecfg:myzone> info

Then do:

Code:

zonecfg:myzone> verify
zonecfg:myzone> commit 
zonecfg:myzone> exit

Whether this has to be set during the zone creation stage rather than afterwards, I do not know, I imagine it has to be during the zone creation stage!

Please see:
Solaris Zone Management
and:
Create Sparse Root Solaris Zone