I've been experimenting and I think I can get something similar to the V-Ray RT trick using Octane's native maps. Try the following:
1 - Add a RGB Image
map to the materials maps slots, e.g. diffuse.
2 - Add a XYZ to UVW
map to the RGB Image map's Projection
3 - Change the XYZ to UVW map's Coordinate Space
to World space
4 - Add a 3d Transform
map to the XYZ to UVW map's Transform slot.
5 - Change X Rotation
6 - You can now use the remaining Rotation, Scale and Translation settings to position the map where you need it.
Here's how this looks with a UVW template applied.
I hope that helps, please let me know if you have any further questions.