Possession and YOUR powers, As with cyberware? Options

[Aerospider]

So I'm putting together a new character to try out the whole possession thing and, after settling on a rastafarian-vampire-(sukuyan)-conjurer-healer-face, I find a gap in the RAW: can the possessing spirit use the host's powers? No mention in SR4a or SM, so what do you reckon?

Possession is highly-powered as it is, so should they not work at all?
Maybe it should be considered as with cyberware: automatic examples (bone lacing, regeneration) do still work automatically but anything requiring activation or control (cybergun, mist form) can't be communicated with.

Then there's the channelling metamagic which allows the magician fine motor control and skill use. Should that therefore allow full access to powers?


With all this in mind, has the following sillinness ever been posed before? (For it to work you do have to ignore the one-hour time limit for boosting an attribute after draining essence, but that's just plain sense since otherwise you could only do it a few times a year.)

Vampire of a possession tradition, Body 5 Magic 5 Essence 5 Drain Resistance 9, Channelling metamagic

Drain Essence, raising it to 12 (double natural maximum)
Boost Magic by 6 to 11 (Essence drops to 6)
Summon a Force 10 spirit
Be possessed by spirit
Vessel uses spirit's Essence and Magic ratings of 10
Drain Essence, raising it to 20
Boost Magic to 20 (Essence drops to 10)
Summon a Force 20 spirit
Kick out the old spirit and take in the new one
Repeat

You would need to keep healing the drain damage the mundane way, the Essence draining would get more and more time-consuming and since each increase in Force adds on 1/2 a box to the damage track but adds 2/3 onto the expected drain damage there is a cap on how far you can go, but theoretically this is a way for a level 1 initiate to whack their stats up to dragon-scaring levels. Now I just have to find a GM who'll allow it ...