So, this doesnt work to access one bone?

Also maybe do this if you script:

setChannel(channelname, matrix)

Accepts a string channelname specifying the name of a valid action channel or bone name, and a 4x4 matrix (a list of four lists of four floats each) specifying an overriding transformation matrix for that bone. Note that the transformations are in local bone space (i.e. the matrix is an offset from the bone’s rest position).
This function will override the data contained in the action (if any) for one frame only. On the subsequent frame, the action will revert to its normal course, unless the channel name passed to setChannel is not specified in the action. If you wish to override the action for more than one frame, this method must be called on each frame.
Note that the override specified in this method will take priority over all other actuators.

Found here:

I guess its the same as using the action actuator for 1 property?:o