Both switches can be configured for core PID by using the configure command. CorePID is the default for all brocade switches.
You need to disable the switch (switchdisable) prior to running the configure command and chaning the PID format.
There is also the WWN based dynamic PID format which does not need you to disable the switch. But I'm unsure as to how this will influence hosts which bind by PID, especially AIX systems.
Check pg 21-23 in the 6.3 FOS admin guide. You will find more details about the configure command in the CLI guide.