This is a case where the Roffe corollary applies. IIDSYCYC + IISYCYBWC
If it doesn't say you can, you can't: The rule book does not have to specify that the power steering system be run fully connected. As long as it does not say that you CAN, then you cannot alter the system.

However....
If it says you can, you bloody well can: pulleys are free - a smartly designed pulley with a bearing integrated into it somewhere might be doable (though I have never seen it done).

I would make sure I really needed to before I went to that level of effort though.