Your problem is here "I'm using the newest usbloader gx".
Newest, or latest doesn't mean anything for a program, and will not help users understand which version you have.
You should always give the real version number because the newest today will be old tomorrow. If there's an update this evening and someone is reading your message, he will think you have updated to the new one when you didn't and it will create misunderstandings.
Your real problem now:
You are using the latest official release as of today (USBloaderGX v2.3).
This version doesn't support launching channels on emulated nand. That's why you don't have that menu in the settings.
The version you think is the newest is not the newest.
The newest version (today r1147) is a beta version not available through the internal update menu of the loader.
It's only available for beta testers and require a manual download if you really want that version.
It's on the official website, in the beta issue thread.
If you install that version :
Don't follow your tutorial, or what the person said to you, it's already old.
Don't go to the settings > Laoder settings > Loader mode.
instead go to : Menu at the top of the screen > Loader mode icon (the one with a cover and a channel) > select which Source you want to see :
[] Wii games (from usb)
[] Channels from real nand
[] Channels from Emulated Nand Channel
You can select multiple sources at the same time now.