The only capensis doing okay in my collection is a specimen purchased from Hong Yee about two months back. This small specimen is place under a transparent cup in an effort to increase the humidity and now grows and dew very well. The plant is plalce at the corridor where it is very windy and the humidity is low. If you wish to try this method, please watch out for fungus, which can easily grow without you noticing.
This specimen gets full sun for about three hours in the morning. So, I think heat might not be a serious problem. Humidity could be the issue here.