I watched the pose mixer tutorial multiple times without success. I have also watched many of Reallusions tutorials on animation.
The problem:  I have a character in a standing idle pose (Idle03 F from Camilla).  I found hand, arm and head motions that I like from another pose (Meeting Motions), but that pose is sitting not standing.
I have tried lots of things and combitations of things with no success. 
If I Align / Head she is sitting in the air.
If I use pose mixer to mask out the legs (or anything else since I was exprimenting) the sitting animation is unchanged - she sits and waives her arms.
If I keyframe the legs before the sitting animation then paste the keyframes once the sitting motion starts, it doesn nothing - she is still sitting. - this is really puzzling - she is ignoring the new keyframes.
If I paste the leg keyframes after the sitting motion, she spends the sitting motion time moving slowly down. A keyframe at the end of the sitting motion makes her pop up.
Sample Motion Clip / All parts - delete the legs, put in the keyframes from the idle - she still sits.
I turned on Motion Modifier to lock the bottom half, but that didn't work.
Animation layer seems to require that I do the animating by hand, which will look terrible (my lack of skillz!) - I see no way to copy / paste a pose in the Animation Layer
I can probably move the legs by hand, but that is usually tedious and ugly - on some occasions I have had to move the legs (or whatever part) every frame to make it work!
If I do have to move the legs by hand, this is not repeatable for the dozen or so clips in this project and the hundreds/thousands more ahead of me in my lifetime
What is the easy way (that I am missing!!!) to combine these animations?
Thanks!