I am trying to track down a copy of the Italian TV show, Interbang from the 1980's. (edit: found as of 2017, see below)

I used to watch the show dubbed in English on the tv station "The Children's Channel". That was a british cable station.

All I personally have is vague memories. I remember the episode starting by saying "episode 23" or whatever printed at the bottom of the screen.
The following information was supplied by Camilla Drefvenborg, from Sweden who also saw this on the Children's Channel. (Was it on any other channel?)
The two guys were brothers, one of which I think was named Luigi.
The man dressed all in black was "the killer", a contract hit-man trying to find the little towers and get back the ones they'd already found.
The old man who gave them the task of finding the towers was, I believe, killed by the killer in the first episode.
He was also the one who had originally hidden the towers all over the country, and he had marked the clues to them with the Interbang symbol( ‽ ). Each tower had an associated riddle, the solution to which would lead to it. The whole thing, if I remember correctly, was organised as a treasure hunt, with each tower having the riddle of the next one.
The one who hired the killer also knows the towers' secret.
The last episode ends with all the little towers being placed in order inside the real one by the man who hired the killer. The tower promptly took off into space (seriously). He and/or the killer was trapped inside.
The towers looked identical to a common souvenir, which frequently caused wild goose-chases. They were not ordinary, however. Each tower had its own associated colour, even though they were all white on the outside, and all of them had magical properties.
The Interbang symbol was a question mark superimposed on an exclamation point.
The brothers and the killer travelled all around Italy, not just Pisa.
The series was very poorly dubbed into English, probably from the original Italian.
I think the killer's hat was a black cowboy hat.

29/04/04: I am told that one of the brothers names was Gianni
and that at the end, the Killer was in the real Pisa tower, but he put the little towers in the wrong order, so he never found the treasure (so the tower went into space).

28/06/17 The series is now available on youtube. The search is finally over.

Any information is required. Please Email.