I obtained two different specimens of Hoya endauensis in the summer of 2013.  One was obtained on Ebay from a Florida vendor and one was obtained from Joni at SRQ Hoyas.  I struggled with both plants and eventually lost the one from Ebay.  The one from Joni was maddening as well; as soon as it would start to grow a little, I would get excited, it would stop and die back sitting there for months before it would try to grow again.  I assumed that it was a watering issue, and I tried various watering regimes never getting it right.