Upgrading DNS/DHCP from OES2 sp1 to OES11 sp1

Hi All,

At this moment we are running a couple of servers with OES2 sp1. One of these servers is our main server (server A) which holds the master replica and only runs DNS and DHCP. Another server is our backup server (server B), also OES2 sp1 and runs a secondary DNS and DHCP server, contains a read-write replica, and our backup software to a LTO4 tape drive which will be replaced by a LTO5 drive. We can't do an inplace upgrade, so we want to completely wipe the server and just install OES11 sp1, and DNS and DHCP.
So we think below are the steps we have to follow.

- First remove the read-write replica from server B
- stop the DNS and DHCP services on server B
- then remove the server B from the replica ring
- Remove all "old" objects from this server B from the tree
- Install OES11 sp1 on server B and DNS and DHCP again. (Server B will have the same name and ip address)

My question is: are those steps correct , and are there any problems regarding a primary DNS and DHCP server on OES2 sp1(server A) in combination with a secondary DNS DHCP on OES11 sp1 (server B)?

Regards,

Mark