GeomFill_ConstrainedFilling problem

Hello dear OCC users,

Using the class GeomFill_ConstrainedFilling to create a surface bounded by 3 BSpline curves I get a very curved BSplineSurface, which is not what one might expect. I use the following code:

Handle_Geom_BSplineSurface aSurf = NULL;
Handle_Geom_Curve c1=;
Handle_Geom_Curve c2=;
Handle_Geom_Curve c3=;
Standard_Real U1b=, U1e=; //first and last parameter of each curve as they might be trimmed
Standard_Real U2b=, U2e=;
Standard_Real U3b=, U3e=;

Handle_GeomAdaptor_HCurve A1= new GeomAdaptor_HCurve(c1, U1b, U1e);
Handle_GeomAdaptor_HCurve A2= new GeomAdaptor_HCurve(c2, U2b, U2e);
Handle_GeomAdaptor_HCurve A3= new GeomAdaptor_HCurve(c3, U3b, U3e);

Standard_Real tol = 1.e-4;
Handle_GeomFill_SimpleBound B1 = new GeomFill_SimpleBound(A1, tol, Precision::Angular());
Handle_GeomFill_SimpleBound B2 = new GeomFill_SimpleBound(A2, tol, Precision::Angular());
Handle_GeomFill_SimpleBound B3 = new GeomFill_SimpleBound(A3, tol, Precision::Angular());

Standard_Integer max_deg = 8;
Standard_Integer max_seg = 2;
GeomFill_ConstrainedFilling aFill(max_deg, max_seg);
aFill.Init(b1, b2, b3, Standard_False);
aSurf = aFill.Surface();

Is something wrong with the above code? I have tried to bypass this problem by using GeomFill_BSplineCurves with CoonsStyle but this class failed in most cases. My OCC version is 6.3 under MSVS 2008.

I would gratefull for any help.
best regards

Konstantinos Iatridis