Hello, here's my method for this kind of surface.

For technical explanation -> Michael will maybe answer you.

Based on my little xp, I would say network like to work with 4 curves.
So I split (trim) the base curve with the middle one.
The curves selection order is important in this case (I thought Moi is resolving it automatically, but some selection combo don't work I don't know why).

This method will put the pole surface on the front of the object, so the result is quite ok.




(I think it's the worse .gif capture I ever made)