There is no direct upgrade path from DP 6.0. On your original cell manager, you would have to stop DP, and make a copy of
/etc/opt/omni/server Configuration Files
You would have to install DP 7 on your new server, then, you should be able to just put this directory back into place
The IDB is more problematical. I would recommend that you do a 'writedb/readdb' prior to the Upgrade to compress the IDB, then back it up to Tape. Upgrade to DP 7, install the patch bundles, Import the tape, and restore the IDB
However, your version of DP is so old, I can't guarantee that this method will work. Perhaps doing a 'readdb' after moving over to the new DP would also work.
install DP 7 on the HP-UX cluster following the instructions in the installation guide. Make sure the MC/ServiceGuard package is configured properly before you start to install. On the old server make a writedb and copy the export to the new server; import it using readdb. Stop the cluster package, and manually mount the shared directory you installed DP on. Copy from the old server /etc/opt/omni/config/server to the new server, Copy DCBF, MSG and META directories (/var/opt/omni/...) to the new server. Start the cluster package and you are done.