I've just stripped a room in my new house.
Try taking to it with a scraper before you do anything. Knock off lots
of those evil woodchips. It will make a mess, but you'll be left with
lots of little holes with exposed paper behind them. This worked better
than trying to score for me.
Then use a steamer as normal - the holes you've made will allow the
steam to get in and behind the paper.
Who invented woodchip paper anyway?! Damn stuff...