@GalaxyGuy yes I have the same screen in RSS however it remains greyed out even with the DCM online. That said, this configuration option is only to modify the card bit string format and there is no actual field to enter the facility code number itself.
An old Honeywell technical bulletin for the Dimension panel clearly states this option is "not enabled at this time" but that was back in 2009 and I would have thought it should be implemented by now. Considering it's normal industry practice and to do without comprises security.
Honeywell probably works under the assumption the majority purchase wiegand card readers with a "fixed" facility code rather than passing through the facility code and allowing the panel to authorise it.