BG2 Sewer Puzzle Question (Spoilers)

[CCF]

This question is more about game mechanics than how to solve it.

How do I place the proper items in the pipes? I get the "circle" for use
when I move the cursor over the sewer pipes but how do I get the game to
know to place any particular item in the pipes. The character doiing the
"using" has all the pieces I have but when I click on the pipes I get a
wrong order message but no way to tell the game whihc items I want to
place in the pipes.

I am also, a mix perplexed as to where the 4th item is. I've got the
hand, the wand and the ring but can't find a 4th item. Any ideas?

[Jonathan Epp]

Don't worry about using the wrong item in the wrong pipe. The game
will always use the right item for the right pipe, you just have to
click the pipes in the proper order.

As for the 4th item, it has something to do with whats-his-name and
his carrion crawler.
(keep reading for a bigger spoiler)

You have to kill the carrion crawler (sacrifice a friend).

Jonathan