Actually I found that the microphone is detected, but somehow not working.
I am attaching a screenshot of the capture devices from PulseAudio.
I pressed the "Show Volume Levels" button within Properties for both "sources" and one of them was completely dead, and the other one showing some constant activity, regardless of I was speaking or not, more like noise than actually recording probably.
Any ideas? All I am trying to do is use Skype.
Thanks a lot for your patience and help