using 7.2 & 7.3 together gives problems....

Hi. I'm trying to use both 7.2 (port 5432) and 7.3 (port 5433) and when I
configured it, I put that port in the configuration. I was able to follow
the instructions successfully until I wanted to start the database:

/usr/bin/pg7.3_ctl -D /var/lib/pgsql7.3/data -l logfile start

and got this error in the log:

FATAL 1: The data directory was initialized by PostgreSQL version 7.3,
which is not compatible with this version 7.2.

I copied the pg_ctl script to /usr/bin, and renamed it pg7.3_ctl so it would
not remove the one for version 7.2 after trying to start it up got that
error in the log.

I did not see a new "postmaster" script for 7.3 anywhere in the
distribution, so I'm not sure if that is what I need. Can I use the same
postmaster from 7.2 for 7.3? Anyone have a suggestion as to what to do?

Thanks!
Robert

O/S: Mandrake 8.2
installed: postgresql-7.3.2