WLC 5508 HA SSO configuration failure

Question

I've just replaced an older 5508 with two new 5508 controllers that we wanted to run in redundancy mode.  I've followed the directions here: to configure my units.  at this time i have my management, and redundancy management IP addresses configured in the same vlan on both units, also the service port addresses are in the same vlan, and the virtual interface is the same on both units.  I setup the mirrored reference in the redundancy global configuration for redundancy mgmt IP and Peer redundancy mgmt IP on both units.  I have designated the primary and the secondary units.  after doing all of this i connected (with a patch cable) the RP ports on both units.  On either unit i enable the SSO option and get the following message:
"Please configure Redundancy Management VLAN before enabling redundancy"
Clicking OK on this disables the option and returns me to the redundancy global configuration page.  I have searched all over and have been unable to find a working resolution for this problem.  I'm not finding much reference to this at all actually.
Thanks in advance.
Beer

Answer 1

I read that but i'm confused as to what it actually means.  I have no redundancy VLAN unless it refers to the network created by the two service port IP addresses.  the devices are setup back to back, and only connect through the RP ports on each device.  here are the steps i took in setting this up.  before taking these steps the primary unit was configured and fully operational and the secondary only had a management ip address on it.  (I expected the secondary to sync it's configuration from the primary so did not set anything up further than needed for connectivity.)
Log into both controllers using their web interfaces
Navigate Controller > Interfaces
Set the Management IP addressBoth units must have the management addresses within the same VLAN
Set the redundancy-management IP addressBoth units must have the redundancy management address  in the same VLAN as the management interfaces
Set the Service-port Ip addressBoth units should be setup so their service ports are in the same VLAN
Set the virtual port IP addressThis should be the same on both units.
Navigate to Controller > redundancy > Global configuration
Verify the redundancy mgmt IP is prepopulated with the IP address from the redundancy-Management interface
Set the Peer redundancy mgmt IPThis is the redundancy management IP Address form the opposing WLC
On the primary unit set the redundant unit to Primary
On the secondary unit set the redundant unit to secondary
Click apply on both units
Verify physical connection is in place between the RP ports on both WLC units
Set the SSO option to Enable and click Apply on both units, starting with the primary unitThis will trigger a reboot on each unit after clicking apply.  The redundancy configuration setup will cause both units to reboot 2-3 times as the configuration is synced from the primary unit to the secondary unit
Did I somehow miss a critical step in this process?