I add a new pad in the source zone.
Click this pad and press Ctrl+E twice. Now this pad is extended to the whole polygon.
But the Paste and Mask layers are altered. So I edit the pad properties and uncheck all the layers.
Now it is correct.
I did the same in the drain zone.
To avoid adding pins that don’t really exist, I renamed all the pins with the name G S D. Used a 3 pins symbol with pins named G S D.
And it works!