Correct name for Hoya multiflora

I bought a plant labelled Hoya multiflora. I have seen it also called;

Centrostemma multiflora
Cyrtoceras floribundum
Hoya javanica

Are these all synonyms for the same plant?. If not how do I know the correct name of the plant which I purchased.

HI....if you go to the HoyasRus forum on MSN, look in David Liddle's pictures. I think it is on the 2nd page where he shows the different buds and flowers of all three.

Carol