I only found this Swedish closed auction: http://www.tradera.com/hoya-sp-vietnam-gps-6262-auktion_160509_189178080. There is a photo but no culture info on the page. Some browsers can translate it for you.

I would ask whoever you got it from if they are available - or start with general middle of the road hoya culture and watch how it reacts to different things.

Mari11...I have this one...It's a decent grower, very beautiful, gets red leaves if exposed to sunlight. Water it heavily, but don't leave it sitting in water. Water again once it gets dry. It seems to tolerate most temperatures, though certainly not cold...60's to 90's work best. Likes very bright light, or sunshine. It looks like any one of the finlaysonii's. I hope that this helps..you have a great plant, congratulations! Fondly, Patrick

Thank you, greentoe, for taking time to look it for me and giving advice, and thank you, Patrick, for sharing your experience! It's great to know in advance, that the plant is worth growing, it makes waiting very exciting.