Basically there is no switch between them as far as I can find out. All the controls are already there on the picker.
However, as you can see on my screen capture above, the hand IK has been left behind... According to the AnimSchool forums, you need to press the 'b' button next to the IK control if you want them to follow the rig. I don't know if they will permanently follow or if you need to click on it every time (forum does not say) but obviously I should have done this from the start. Clicking on the b button now does nothing. The FK2IK and IK2FK switches also do nothing (red error message appears at the bottom of Maya window).
Now that I understand a bit more about what I'm actually looking at, it appears I've been animating the feet and knee vectors in IK and everything else in FK. Admittedly, my understanding of IK/FK is pretty shocking. I don't really know the advantages of animating in either and the only difference I know is that once you key something in IK that control stays where it is in space and is not affected by other controls while FK controls are affected by other controls. I really ought to learn more about it.
Anyway, as far as I can tell so far, this is just untidy and might make some things difficult for me. However, it *should not* be too much of a problem to carry on with the way I've been animating. Should remember this for the next assignment I start though.
Update on mime animation. Walk is just about fixed. Working on the first 200 frames, thoroughly sorting out any problems. I plan to work this way through to the end and then back through it again on splines unless there's a reason it's too early for splines.
11 Second Club forum