Attempting to setup IP phone so when calls come to a line, internal calls will go to voice mail and external calls will forward to a differnet DN.
What seems to be the right settings only the setting for internal takes affect (e.g. Internal No Answer, etc.)
just to add to the great info from Rob make sure the GWs are correctly tagged as OffNet in the config, that's the field used to determine whether to use internal or external rules
if this helps, please rate