Not necessarly true. As with how Campagnolo derailleurs will not just "drop in" in place of a Shimano derailleur, it has to do with the ratio of cable movement to derailleur movement. Shimano has always been good about keeping the same Ratio (except for early indexed Dura-Ace). Campagnolo, has not been so consistant. In fact, it seems with every new cog they add, there's a new ratio to go along with it.

So, the short answer is: maybe.

The long answer is: you may get lucky, or you may strike out completely getting the two to jive together. The likely outcome will be that you'll get some cogs to play nice on one end, while at the other end you'll experience a lot of chatter if not full out skipped shifts.