Cisco DCP3825 and the IGMP Proxy setting

I am trying to either enable or disable the Internet Group Membership Protocol (IGMP) Proxy on my Cox firmware'd Cisco DCP3852.

According to the modem's help guide, it should be located in the Management tab under Administration.

It is not visible.

I believe the option is still available, but it has been hidden by the Cox firmware installed on the modem.

Has anyone been able to find a way to enable or disable the IGMP Proxy setting? I'd really like to be able to use my wired desktop with my Chromecast. 

Elsewhere, If I absolutely have to, how would I go about requesting a different model of modem?