I don't know what you have to do but if its just sliding texture across one of the world axes, you can do it in octane via a transform node linked to position.
if you need to edit UV, you must do it in a modeling software...
To move your UV's in Max try to move the gizmo of your UV map modifier.
I kind of remember that there was an Octane transformation map in Max plugin too (and I already wrote an unpolite response to you about reading the manual ) but while I'm looking at it now, I cant find the transform map anymore.
[edit]
It turns out you can only use it with Octane procedurals. So no transform for images. Seems like your only option is to move the UV gizmo.
Make sure you're not using different map channels for your texture and UV modifier.
If your image is on channel 2 and you're moving the gizmo on channel 1, then nothing will happen.
Hmm..wait..there are no channels when using Octane image.