Unfortunately the 4F 09 does not enable the Broadcast Status Change message for Input changes. It enables the Broadcast Status Change message for Output changes. The Configuration Register controls the generation of Input Status Change messages. Have him consult the EZIOxx Advanced Details document. It describes the 4F 09 as setting “Enables Output Port status change broadcast messages”. What they need to do is enable the Input Port status change broadcast message.
EDIT: the command sequence Indigo is doing for the EZIO8SA is the correct sequence and should be done for all EZIOxx devices where they want to generate Input Status Change messages. That is why the EZIO8SA produced the correct results. The command set is common across the entire EZIOxx family of devices.