Åsa,
I talked to Eric A. Christenson (who described
Asco. insularum as a new species), and
Ascocentrum insularum is a species known from only 2 dried herbarium specimens. The holotype is from an island off the east coast of Borneo (Kalimantan), and the second specimen is from eastern Sulawesi. He says there are no photographs of this species, but has unpublished drawings of the floral dissection of both specimens.
As for
Ascocentrum himalaicum, it is known from Burma, Bhutan, and China. There are also no photographs of this species, but there is a detailed drawing in the type publication. Eric also says that
Asco. himalaicum has terete leaves, which several people have tried to segregate the taxon into it's own unispecific genus. Garay, Seidenfaden, and Christenson do not favor the weakly defined genera, so
Ascocentrum is the genus to use with that taxon, not any other.
Hope this helps! It doesn't seem to probable you will have either species in your collection
-Pat