I suspect the housing has already been damaged as it has twisted. I seem to remember there are locating lugs on the housing which break when it twists. As a result if the housing is not lined up correctly after you're done the oil ways will be out of line and you'll have poor oil pressure.

Sorry can't help with an idea on holding it. I've seen the cap break whilst trying to remove it before. The housing is held on by 1 center bolt (imagine the thread you'd wind a canister oil filter on to). Prob best to price up for a new housing and just remove as required.

Matt