I discover again than a "Sweep" can have any numbers of different profils !
So the "icone" of "Sweep" is some misleading :)

A funny & terrific thing is make a sweep and after select the rails / show Points, Add Points and move the points!!!
In this case (show points enable) does exist a trick for move the last point as a "tangente" ?
(only warm points, and axes seems work not the "tangent" (?) )
For the moment the only I found is draw another line as "tangent" and return to the point for move it on this new line ! It's no so bad :)