Grobmotorix,
The actual goal of my puzzle is to find out more about this mysterious car as well.
Indonesia at the time was a colony of the Netherlands and therefore it could well be that a Dutchman started a company with these cars. It is known that other Dutch makers like Econoom, Simplex and V.L.A.M. exported to Indonesia. Makers from the area, like the Australian Eco, also had an eye on Indonesia. It could have been that a local company made a body on the chassis of a Goliath, eventhough it does not look like a Goliath to me. But that's just me maybe.