OK, perhaps the reason it didn't work is because I spent the last 3 hours in the pub.

Here is an example that does work. This just slaves the rotateZ channels in the right index finger (Posette or Victoria). You have to create a channel to inject the pose into, by Spawn Morph target, in the case of the pz2 below the morph target must be called "Blank01".

Whilst this file only slaves the rotateZ channels, it should in theory be possible to change (or add) any information in the joint channels via a pz2 (or hd2) file. The only thing I know of that you cant do to a channel via a pz2 is create a new one.

Am I on the right track here? Is this what you are trying to do?

{
version
{
number
}

actor rHand
{
channels
{

targetGeom Blank01
{
name CurveIndex
initValue 0
hidden 0
forceLimits 0
min -100000
max 100000
trackingScale 0.004
keys
{
static 0
k 0 0
}
interpStyleLocked 0
}

}
}
actor rIndex1
{
channels
{
rotateZ zrot
{
{
}
valueOpDeltaAdd
Figure
rHand:1
Blank01
deltaAddDelta 20.000000
}

}

}

actor rIndex2
{
channels
{
rotateZ zrot
{
{
}
valueOpDeltaAdd
Figure
rHand:1
Blank01
deltaAddDelta 20.000000
}

}

}

actor rIndex3
{
channels
{
rotateZ zrot
{
{
}
valueOpDeltaAdd
Figure
rHand:1
Blank01
deltaAddDelta 20.000000
}

}

}

figure
{
}
}