linux - Use ldap for auth (via pam) but /etc/passwd for uid and guid -

i newbie on pam , nss please gentle.

i have following scenario:

i have access ldap database have no control on administration (so please not proper fix fix database, know not happen). however, in database users registred , authenticate against not have maintian own user database.

the main problem there no uid or gid information in database , ldap admins refuse add information.

my idea:

configure pam can authenticate against ldap. if user sucessfully authenticates, pam (via pam-script?) creates local user (in /etc/passwd) local unique uid. local user later used nss find uid , guid.

what have done far , question:

i can authenticate against ldap , have idea on how create user @ login failing make nss use "local users" getting uid , gid. how can split login use ldap authentication , uses local files finding uid , guid, shell etc ?