How to make a ComplexShapeElement from BSplineCurves

I am able to use CreateComplexShapeElement1 with LineElements, but when I include a BSpline this fails, even though IsChainableElement returns true. The code below demonstrates the problem. 

I am using V8i version 08.11.09.459

Sub CompoundElementTest()

    Dim oStringElements(1) As ChainableElement
    Dim oBsplineCurve As New BsplineCurve
    Dim axis As Segment3d
    Dim startPt As Point3d
    Dim radius0 As Double
    Dim oElement1 As Element
    
    startPt = Point3dFromXYZ(1, 0, 0)
    axis = Segment3dFromXYZXYZStartEnd(0, 0, 0, 0, 0, 1)
    oBsplineCurve.helix 1, 1, startPt, axis, 1, False, 0.000000000001
    Set oElement1 = CreateBsplineCurveElement1(Nothing, oBsplineCurve)
    Set oStringElements(0) = oElement1
    
    startPt = Point3dFromXYZ(1, 0, 1)
    axis = Segment3dFromXYZXYZStartEnd(0, 0, 1, 0, 0, 2)
    oBsplineCurve.helix 1, 1, startPt, axis, 1, False, 0.000000000001
    Set oElement1 = CreateBsplineCurveElement1(Nothing, oBsplineCurve)
    Set oStringElements(1) = oElement1
        
    Dim oComplexShape As ComplexShapeElement

    Set oComplexShape = CreateComplexShapeElement1(oStringElements, msdFillModeFilled)
    ActiveModelReference.AddElement oComplexShape

End Sub