Now this is a feature I have wanted for quite awhile. SaveNumberAs was the product of one of our DreamBerry ideas. In that DreamBerry I mentioned two issues. First that RIM would default any number you added to your address book as a work number. That issue was fixed in the first version of SaveNumberAs. This recent update now fixes the second part of the DreamBerry which asked to be able to save a number to an existing contact.
Pretty cool! You should be able to pick up the updated app version by going to the store and getting the trial. If you don’t already have a copy you can pick it up for $2 until November 18th.