Unfortunately I haven't this command in WLC526's CLI. I suppose that reason following:
"The WLC526 controller is simple to install and operate; therefore, the controller CLI consists of a limited number of primarily show and debug commands." (extract from Cisco 500 Series Wireless Express Mobility
Controller Configuration Guide).
These commands available:
(Cisco Controller) > config ?
advanced Advanced Configuration.
(Cisco Controller) >config advanced ?
802.11a 802.11a parameters.
802.11b 802.11b parameters.
client-handoff Auto handoff the clients on excessive retires.