Someone else will probably bring this up, but there is a good reason for dialing a digit to access an outside line.  We use a UC520 in our corporate office where most user extensions are 3 digits and start with a "2".  One of my colleagues, we'll call him Bill, has extension "206" for his personal extension which also happens to be the area code for Seattle.  If there is no way to tell the UC560 that I am trying to call Seattle, it will dial Bill everytime I start to dial.

Dialing "9" prior to dialing an outside line is a new procedure that is a pain when you first have to learn it, but eventually becomes second nature.

As for changing the voicemail transfer prefix, go to Configure>Telephony>Voicemail in CCA and change the Direct Transfer Prefix.  Ours is set to "6", but you could change this to "2".  In our example, if I wanted to send a call to Bill's VM, I would simply hit the Transfer key, dial 6206, and hit the transfer key again.

Hope that helps,

Seth