Inserted pauses and passwords in phone number don't work in 3G?

[telmerco]

I have recently upgraded from a 2G to a 3G iPhone and just synced my new phone with all of my old contacts. Some of the stored phone numbers have pauses inserted at the end followed by voicemail box codes, passwords, etc. This worked like a charm on my 2G. However, on my 3G the pauses and following numbers seem to be muted/distorted and they don't work - I always have to follow-up and insert by hand. Has anyone else experienced this problem? Thanks, Colin