Identification: what is this plant?

I work at a local greenhouse and nusery. A customer brought in this picture and asked if we knew what it was. Its very easily propagated by cuttings and easy to grow. When blooming it has a sweet fragrance and drips s clear sticky substance. Can any one help??? N.

 

A species of Hoya or close relative

 

whoa?!?! I never thought there were any upright growing species of hoyas. Thanks now I have a new direction to look.

 

If not a Hoya, then definitely something else in the (sub)family Asclepiadaceae (milkweed family)

 

Try Hoya multiflora, Joe