SR4 Channeling
 

How do I enable my spirits to be channeled? Is there a tick box to enable to denote the changes in attributes and dice pools relative to the channeled spirit?

If you look into the Adjust Tap there is the Option for Spirit Possessions.
But by my understanding of the rules, possession ignores the augmented maximum and HL does not ignore it in this case.

So not shure if it helps you.