HDMI ARC set on Auto but optical output doesn't work

[mfizz]

Hi,

I have been trying to get my home cinema system to work the way i want it to. HT-E4550. I have set the ARC option to Auto.  I assume that would mean that it would toggle between HDMI ARC and optical out as it sees fit. 

I have a media player that i use that connecting via ARC means I do not get DD5.1 or DTS as my TV does not have passthrough. 

How can I make the the home cinema switch between the two without having to physically go into settings and set the HDMI ARC to "OFF"