The elusive Hoya obtusifolia

I found this very large Hoya from a giant fallen tree in southern Johore many years ago. The stem was so thick and the leaves so thick and succulent I initially though it was one of those climbing aroids. From a cutting, a large specimen many metres long was derived which flowered during the evening. The flowers had a mango-like smell I recalled.

Supposedly, this is not a very common plant. My original specimen perished a couple of years ago and I am still looking for a replacement without success.