Hello Martin, many thanks... I didn't understand that I have to select the "entire" joined curved and then Moi asked me to select the vertices... now it looks obviuos...
I have downloaded MoI 2.5 trial some days ago and I'm looking for tutorials and examples to learn t use it. I will continue trying to follow this tutorial, may I ask you something else if (surely) I will need?

thank you
ciao Franz