no answer to the OPs question...
Op I'm pretty sure it can't be done. With several Nissan models little amenities like the digital read display. Are varied with each model of car. If you need a digital read out try this.
Scangauge -
ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool
Thread about it on my350z -
cheap gauge alternative (water/intake temp) - MY350Z.COM Forums
I've had it a while now and it has paid for itself several times. Check it out man, all while joining your local Z club for meets/cruises...