Surface sewing

Actualy, i use BRepAlgo_Sewing to create a surface composed of two parts. But OCC does not create realy only one surface! as it is said in the documentation: BRepAlgo_Sewing::SewedShape()Gives the sewed shape. May be a face, a shell, a solid or a compound.It is not possible to work this this object as if it would be only one surface. So I had to create one myself(i calculate a ruled surface with the free edges of the sewed surface), but it takes long time to do that (there is a lot of conditions to verify),The question is : is there an other solution in OCC to get a real unique surface sewed from others?
thanks...