Hi, never mind. As so many other times (blush) I figured out the answer right after posting the question. I was trying with a test file like the following and with the org-sort (C-c ^) command. I assumed I had to issue the command in the TODO line, which tells me there is "Nothing to sort". Actually it looks like I can do it in any of the Task lines and it works exactly as I wanted.
Orgmode to rule the world! :-) ,---- | * Test | | ** TODO Work on item 1 [2/12] | + [ ] Task a | + [ ] Task b | + [ ] Task c | + [ ] Task d | + [ ] Task f | + [ ] Task h | + [ ] Task i | + [ ] Task j | + [ ] Task k | + [ ] Task l | + [X] Task e | + [X] Task g `---- -- Ángel de Vicente http://angel-de-vicente.blogspot.com/