glaring loop problem

So if anyone knows the answer to this one it'd be good to know. Of course the 4000 does looping to any sample, it works fine but here's the problem. You can set loop start and loop end points, xfade them, alternate back forwards, but I can't set loop position, meaning both the start and end points at the same time. This is pretty crucial to setting loops in the right place of a sample.

Anyone know how to adjust loop positions that'd be great to know.

In case anyone couldn't find this on their own, I was messing around and found out if you set the end field to anything but end you'll get start and end points locked together. Which is mandatory for good looping