iNum calls don't actually use a dial plan entry. In fact for them to work properly, the 883 prefixed number must NOT match any dial plan entry.
Try disabling the default dial plan entry and get to a point where the "Test Call" feature displays something like:
Code:
A call to:8835100xxxxxxxx will not get forwarded
This is message is a bit misleading and will be fixed to reflect iNum coonected calls very soon.