When it comes to ROBOTC 4.x, I can tell you the is no Mindstorms +NXT Tetrix menu option. Instead, you select the NXT as your platform, then select the External Motor/Servo Controllers option at the bottom of the Platform Type submenu. As to the option not appearing in 3.x, I'm unfortunately at a loss there.
Burning Lights Programming
FTC Team 6100 Chariots of Fire - Programmer (2012-2013)
FTC Team 7468 Blue Chariots of Fire - Programmer (2013-2014)
Check out our team website at http://cof7468.weebly.com/