BRepOffsetAPI_MakePipe.Generated()

Hi!

Is somebody know what is the arguments for the Generated Method of BRepOffsetAPI_MakePipe.

In the headerfile i saw :
TopoDS_Shape Generated(TopoDS_Shape SSpine, TopoDS_Shape SProfil);

When i use it, the return shape is always null.

Suppose I have done a pipe from:
TopoDS_Wire AWire (who is the Spine)
TopoDS_Face AFace (who is the Profil)
I use:
BRepOffsetAPI_MakePipe FairePipe(AWire,AFace);

The method FairePipe.FirstShape() and
FairePipe.LastShape() work very well, but how can i found the others faces?

Genevieve