To have flexibility in the placement of a logo in your example I would do the following:
Use 2 UV sets, one for the main texture/material and one for the logo placement.
But it doesn't export correctly (no texture at all is transmitted to octane actually).
I think that the mixer node is not taken into account here by the exporter. Any thought on this face?
edit: ok just seen your reply above. But even with one UV it doesn't export, maybe the exporter only takes image maps on the diffuse slot but no mixer node?