I'm reasonably convinced the 'Soeb' came from 'Subud', which is an Islamic cult to which Ann Dunham and Loretta Fuddy (interestingly, and not coincidentally) belonged.
HF
You don’t think it’s possible that the name relates to one of the elite members of this family, do you?
http://banihasan.blogspot.com.au/search/label/BANI%20NOTO.SOEBARKAH
There’s also a village by that name in Java. A SOEBARKAH member of the military was a coffin-bearer at the funeral of Suharto.
Try Google.