my toughest opponent - passive opponent NL

[Vinetou]

I have a lot of problems playing against passive opponents who never raise, they only check call or check fold all the time. They play bottom pair the same as top two pair or a set, they never raise, never reraise... I just don't know how to put them on a hand, don't know when to bluff them and when to check multiple streets. I am not talking about loose passive calling stations, against those you just value bet, but these guys seem to know what they are doing. For example, they will check call one time with bottom pair, but check fold it on the turn. But I don't know whether to fire the turn or not because they might have the nuts. Or they might check call two times with middle pair and then I check river IP and go crazy when they show me middle pair because I know they would fold on the river if I bet (they are not calling stations!). Or I make a three barrell bluff and they show me flopped set (and BTW, they didn't move in on the river with it - no, they just called again!).

I always seem to lose money against these guys and I feel that this strategy is the best against a superaggressive guy like me. It is really the most profitable strategy against me and I don't know how to beat them and I don't even know the secret of their success. It is totally different than what we learn here - aggression, aggression, aggression.

Anyone has some similar experience?