Hi Burr, there is no way to separate the seam using control point editing, because the control point editor is built to keep the seam intact.

Otherwise if it did not do that, it would not really be possible to use control point editing to sculpt a smooth object like in this example:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1514.1

But yeah if you cut the surface so that your object is made up of 2 surfaces rather than one single closed surface, then you can get what you want, it looks like that is what you used for your example?

If you want to only have one single surface, then an alternate way to go would be to make 2 curves, and do a loft between them like this:





You have to position the closed curve so that the seam of the closed curve is in a good location for that, it will not do an automatic adjustement of the seam location for this kind of case.

Does that do what you need?

- Michael