Just code your RNS-E to let it know that you've got bluetooth (or have the supplier code it for you, if you're buying it form a reputable supplier) and then it will go beyond what you're used to!
You will be able to DIAL from the RNS-E, you'll be able to see phone lists on the screen, the incoming caller's name will pop up etc... life is pretty wonderful with OEM BT and RNS-E.
Your RNS will need to be coded for BT, and any other options which you have, such as multi-function steering wheel, digital radio etc... if in doubt, look on the Ross-Tech wiki under A3 (8P), and then look in 'navigation', under coding.
Keith