I've done that too, but with a different kind of jump than the regular jump. There's lots of interesting stuff in the final area of Sekto's dam, all of which I'll still try to show as soon as I can. I think that I'll edit this post to put in the next segment of the speedrun, but it'll probably take longer to do than most of the other segments will.
EDIT: Hugh, it took me all day to do this, but here it is: Segment 3 - Part 1
http://www.youtube.com/watch?v=09tSoUAa_d8
Segment 3 - Part 2 will be posted on this thread before the end of this weekend; if you don't like the first part of this, ignore the CUT, this isn't an actual speedrun in the first place and I got desperate, then you will love the next part that actually has some glitches involved!