5.1 sound through HDMI

From what a friend of mine told me and also readed in the manual, digital sound (5.1) is only available when using Toslink output of WD Live. Now I read that this is also available through HDMI (switching from stereo to digital in menus).

So, is this true and is there any difference between HDMI and Toslink. Any advantage buying an optical cable and connecting it to my AV ?

Thanks.

If you have HDMI capability, use it.   It can carry more data than Toslink;  Toslink won’t carry AC3-HD, but HDMI will.