How to use LDAP passwd at 4.9 ?

[Frank]

Hi

I have a centralized mail server that actually use
NIS to access users's passwd, as we use a LDAP server
to authenticate all users I had to setup a YP <--> LDAP
gateway to let our mail server access to the LDAP.

The YP <--> LDAP software is from HPUX 11.11
but it suffers of some bugs and sometime
the NIS client on the mail server cannot contact
the pseudo NIS server that runs on YP/LDAP gateway.

The problem is the mail server runs 4.9-R that cannot
support nss_ldap and it is not possible to upgrade
to 5.xx for now due to other softwares that run
on it.

My question ( at last ... ) is there a possibility
to dump the LDAP database from the mail server 
and format it ( thru a shell script ) into 
a /etc/passwd file format , then integrate it
to the LOCAL passwd file ?

at last is it possible to modify the /etc/master.passwd
file with a shell script to add some entries in it the
modify the passwd database WITHOUT using vipw ?

Thanks