When you manually dial on a land line or with other cell phones, does it matter if you omit the "(0)"? Is it in EVERY number? What happens if you manually dial the iPhone with the (0)?
I don't know the official "standard" dialing format where you are, but what was programed into the iOS doesn't appear to require those characters, and the phone can't recognize numbers with them as telephone numbers.
In the US, land line carriers usually require a "1" added to the beginning of a long distance call to go through. Most cell carriers don't need the 1, but the call goes through with or without it.
You can provide feedback to Apple:
http://www.apple.com/feedback/iphone.html