Great work Simota! Not trying to hog this thread, but just as an FYI you guys can reference my thread in regards to disassembly of the entire gauge cluster for modification here:
Nissan 370Z Forum - DIGItonium's Album: Gauge Cluster Modification
You will have to do this the first time in order to get the Fuel/Temp gauge bezel removed. Then you can reassemble the entire gauge cluster and reinstall it without the bezel. Once the bezel is modified (painted, sticker, etc.), you can simply pop it back in.
Nissan 370Z Forum - DIGItonium's Album: Gauge Cluster Modification
On a side note, I'm currently modifying the oil temp and batt volt cluster. The faces will be sent out to Black Cat Custom, so he will make the new gauge faces available for customization. The only drawback is that the entire dash needs to be removed to get to the cluster.
Simota, you should paint the bezel black!