Moving Linked Poseballs with a Script

I have a project with several pose balls that I need to be able to move with a script (and have the Sitting avatar moved and rotated with the Balls).

I am useing llSetPos and llSetLocalRot to set the position and Rotation of the Pose Balls.
I would expect the Avatar to move with the Pose Ball after the movement commands are issued, however it stays in it's starting seated position. If I stand up and then sit back down the avatar sit's in the modified Sit Position.

I would expect thatthe avatar would move with the pose ball in a linked set just like it would if I grabed and moved an unlinked object that the avatar was sitting on.

Is this a known issue, or is there a silly trick I am missing?

Thank you
Lor

It's not actually an issue, but it is known.

Avatars are like any other prim in the link set. So, moving any one prim (except the parent prim, which moves the whole set) changes only that one prim.

Alas. We need hierarchical link sets, yes?

Yes!
Come join the party at Prop 607.