Hi JnatureLy,
We were given this solution on Call Park for 9.1.7 a couple of months ago, for 9608's. We noticed that when we entered that source number, it did the trick at first. Then we did a mergable change (added a user button on a phone), and it stopped working. We did this lab test time and time again. A mergeable change caused unparking of the call to require Connect softkey, regardless of this entry in the No User source number tab. We told Avaya about this too, and my ticket stayed open for weeks with same update "they were working on it". Finally told them we couldn't wait on them any longer and we downgraded our customer to 9.1 SP6. Problem solved, and they closed my ticket a couple of weeks ago.