no LiveView with headphone on 5D2 and ML2.3 and Sescom DSLR-5DMKII-HOCM

[dvp]

I lose live view when I plug in headphone into a/v jack on my 5D2 using Sescom HOCF cable.
I do hear sound through headphone - just no live view...
Is there a setting some where that I am missing?
Also, I do not find option to enable or disable headphone in ML2.3 even though it shows in the audio settings: hidden: Headphone Monit.
Can anyone help me? I would be most appreciative, it is most vexing.
Thank you

[Malcolm Debono]

Headphone monitoring should be switched on from the audio menu. If it's not visible, you need to press Menu so that all hidden menu items are shown.

[dvp]

Thank you very much for your help.
Works great now.