Now the good news: the idea and the design are, if we do not count the fabric choice) perfect. So, the positive outcome is double: first, it becomes a new project (I must find some real leather and make it again, but transpirable); second, I learnt something really important: never use non-transpirable, faux leather fabric ever again.
In the making of the dress, I kind of learnt some tricks to sew the faux leather in the machine. If the fabric is sticky and makes it difficult for the machine teeth to move it, cover the seam to sew with some pattern paper strips and remove them after having sewn it. It works perfect.
Here I am wearing it with my wonderful new Dr. Martens kick ass boots, beautiful with long socks.