pagheca,
Well depending on the number of points to make the curve, you could either use a spline or a curve through reference points. Dimension each point and then put the point dimensions into a design table. You can write your equation in the design table to update the point dimensions. If the equation is linked to some parameter in the model that changes the curve, then by allowing model updates in the design table, all you would have to do is open the design table so the curve point info would update and then close the design table.
Regards,
Regg