Struggling with creating a new mecanim animation

I am about as frustrated as I could be with trying to figure out animation in Unity 4. I have Unity Pro and have many things figured out, though am still new to it for sure. I have no trouble doing things with the raw mocap animations - creating controllers, blend trees, etc. - basically working with existing animations. But what I really want to do is to create some very simple animations from scratch. But when I try to record one, I get errors like "Keyframing for humanoid rig is not supported!" I've looked at just about every tutorial on youtube. They all use existing animations. I even have trouble importing, on some FBX files Unity just crashes or hangs on import. The few that I've been able to import successfully, seem to be fine in preview, but then when I put them into a controller and wire up to an avatar, the avatar is nowhere to be found when I run the app. The animations in the asset store are woefully inadequate, unless you want something related to fighting, in which case you have a million options. But if you want a simple idle animation of a guy sitting at a table smoking a cigarette, for example, well forget it. Can ANYONE point me to a tutorial of creating a retargetable mecanim-based animation, within unity, where I simply click record, and add keyframes where I modify the poses of the avatar?