Carliro,
You're using custom views, so the software isn't going to "know" what orientation your custom view is going to be set until you go through those motions and name the view. On top of that, your custom views are not universally defined. For an icon to work, NX would have to have that information before you had any parts created and be able to embed that information into the defaults (settings or coding). The "canned" views (TOP, FRONT, RIGHT, LEFT, etc) are all predefined and based on the Absolute CSYS so Siemens is able to match a view name with a specific orientation.
While I won't argue that you have a valid point or a valid frustration, it's been this way for as long as I've used UG/NX (since UG v11) and I'm sure some users or recently retired Siemens employees could go even further back than that.
If it were me, I'd call GTAC and log an ER and tell them I wanted the ability to add Custom Views to the Canned View orientation commands and explain how this would be an improvement. You might explain it as a checkbox on the Custom View dialog that allows you check it if you want the views added to the Orient View/Replace View command group as well as the benefit of doing this (fewer mouse clicks, faster and easier access to the Custom Views, etc. Unchecking the box would remove the Custom Views as a choice on the Orient View/Replace View commands.
Hope that makes sense.
Tim Flater
NX Designer
NX 9.0.3.4 Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB