Problems creating tail fin

I am not sure if I can clearly explain my issue, but I amgoing to give it a shot. I am trying to model a tail fin thatreally has a pretty simple geometry. I have two well definedsections: the root, a section about midway up on the fin. I candefine those two sections, and loft a solid between them. That partis easy.

To finish the geometry, I need to extend the surfaces from the loftthat I have perfomed (note that they are tapered) up to aprescribed height, and then cut it with a plane that sits an angle.I have the cut plane defined, so I just need guidance on how toextend the surfaces on the lofted volume. I have tried a fewthings, but I have not been able to work it out.

I am unable to attach a .sldprt or .bmp. I get an error that saysthat they are not valid file types. I could not find any rulesabout uploading files. If you can point me to guidance on attachingfiles, I will upload images.SolidworksParts And Features