Change Solaris NIS master to Centos 5

I've been running a slave Centos 5 master with no problems for a few
months now. The master is running an old version of SunOS 4.1.4. I
want to make the Centos server the new master and I have read much
documentation on how to do this.

The steps I have left are (taken from
http://home.planet.nl/~snel0369/Chan..._Server.html):

1) Copy the map sources files and the NIS Makefile from the oldserver,
and then rebuild all of the maps:

2) Install copies of the new master server's maps on the old master
server.

3) On the old master server, distribute copies of the new maps to all
NIS slave servers using yppush:

At this point, the old master server is running as a NIS slave, and
the the new master server as an NIS master.

4) Log into the new master server in multiuser mode using the root
account.

5) Remove the old master server from the ypservers map:

6) Distribute the changed ypservers map to other servers:

7) Check whether the new master server's name is included in the new
maps:

Step 1 above is what I am confused about in this situation. If I was
changing from a server with the same OS and version, I think it would
be much simpler. However, the Sun server is old and has been in use
for several years. This means it has a large amount of users and
groups to migrate.

My question is has anyone run into a similar situation and have any
tips? In my mind, the passwd and group files are the most worrisome
since I need to merge the old with the new, disregarding system files
from the old server and including the system files with the new
master.

Since I'm using shadow passwords on Centos what can I do to get the
passwords from the old system recognized by the new system? Thanks
for any help.