creating bezier (or nurbs) curves using COM interface

I'm not actually using VB or VBA, but I am using the COM interface to
Autocad, so maybe someone in using VB might know something about this...

Somewhere I read that an Autocad Spline is represented internally as a NURBS
curve. I have read that a nurbs curve can be represented by a set of
control points, knot-vector, weights and degree. I have also read that a
bezier curve can be represented exactly as a type of nurbs curve (using a
specific knot vector, etc.)

Here is my problem: The COM interface to Autocad seems to be more geared to
scripting user input as opposed to general programming. I think that
because of this the method AddSpline takes the arguments PointsArray,
StartTangent, and EndTangent. These seem to be the types of inputs that
someone actually drawing a curve would give.

What I want to do is to take a bezier (or nurbs) data structure and plop it
into Autocad. AddSpline does not seem to be all that useful for this
because the PointsArray seems to be actual points on the curve and not
really nurbs control points, if I am interpreting this correctly.

The Spline interface seems to appear to be a little more promising (once you
have a curve in Autocad.) It has ControlPoints and Weights and Degree, so
perhaps once I put a curve in to Autocad I can modify it to be the bezier
that I want. But what about the knot vector? And, do the ControlPoints,
Weights, and Degree mean the same thing on this interface object as they
would for a nurbs in another program?

Does anyone have any experience creating nurbs with the vb/vba/com interface
in a way that uses knot-vectors etc.? I am hoping so before I try to
reverse engineer an IAcadSpline into a nurbs. I know from reading posts on
these newsgroups that you can do such things with autolisp and entmake, so
there has to be some way to do it with COM.

Any insight into this problem would be greatly appreciated.

Oh yeah, I'm currently using R14 but plan to upgrade soon.

Thanks,
Andrew W.