Upgrading BIG IP LTM appliances

I am trying to figure out how to upgrade my hardware as well. We are running a single node 1600 on 11.1 code and I we want to migrate to Network based HA Pair 3600 running the same 11.1 code.

 

 

I have the new 3600's racked and cabled and on the network in Network HA mode with new IPs. I have migrated the External Files over and the CRT and Keys. I have attempted to copy over the bigip.conf file but am getting lots of errors during the load of file folders that didn't exist in the common/ dir. I manually created these folders but know its a permissions error.

 

 

What is the best way to migrate the entire config? We would like to reuse the standalone SelfIP as the Floating IP and use new Self IPs on the devices.