If memory serves, Cappa attributes the Verlux name to Etling. Thus far, I have not found any other source or any reliable evidence to support this, however. To my mind it seems unlikely that Etling, as a retailer would have commissioned pieces to be sold under a different name, particularly pieces so close in style as to compete with his named output. Of course I could be wrong & Verlux could be an attempt at establishing an alternative brand.
If anyone has any further information about Verlux and any association with Etling I would be very interested to hear about it. It would be nice to see a catalogue or at least some written source from the time establishing the link.