Some of the mix functions are described here:
http://forums.planetside.co.uk/index.php?topic=2101The Component Mix Vector is similar to the Mix Vector except that it allows mixing of the X, Z and Z components of the vectors independently using the X, Y and Z components of the mix controller. In that sense it works the same as Mix Colour. I decided that it would be safer if Mix Vector only allowed a scalar for the mix controller because that's how vectors are commonly used in vector arithmetic, and a separate Component Mix Vector is there if you want to manipulate the components differently.
Matt