Latitude E5540 no sound output over HDMI cable

When I connect the laptop to a TV using a HDMI cable, there's no sound output via the cable, the sound comes out of the laptop only.

I tried to search for the play-back device by (showing disconnected/hidden devices) but I can only see the Real-Tek Audio device, and there's no HDMI audio play-back device on the list.

I tried uninstalling both of the Audio and Video drivers and re-installing them once again, but still the same problem.

I have an audio device "Realtek ALC3226" and a video device "Intel HD Graphics 4600" , there's are the two drivers that I uninstalled and re-installed, but same problem.

I saw that there's another nVIDIA driver available on the dell website, I tried to install it but the software gives me an error advising that the hardware is not supported.

Specs of my Latitude E5540 can be found here:

www.dell.com/.../GUID-FA08D88F-67D7-4277-A7B9-D872F106A82B

Any Ideas ?