for me, I would do the following:
- in your editor of choice (affinity, Pixelmator etc) , I would overlay the ambient occlusion (at 90%) onto the base colour and export as 1 image.
Then add this image to the colour slot - change OBJ Attribute to -> image
Not 100% sure but don't think Vectorworks can handle normal or height maps. (so no need for them)
If you need to scale image you have to use the absolutely useless 'set by image' button ..!
If you are only using 'shaded' render that's all I'd do...