Unknown Origins
Collectors and cultural hobbyists are quick to ask about the authenticity of the Paiwan beads. Where do the ancient Paiwan beads come from? How old are they? How are they made? Some scholars suggest that it was the ancestors of the Paiwan who brought the beads with them to Taiwan. Ethnographer Chen Chi-lu notes that analysis of the old beads reveals they contain lead but no barium, placing their origin within southeast Asia. The beads might thus date the arrival of the Paiwan people to Taiwan since similar beads are found in other areas of southeast Asia but not among any of the other tribes of Taiwan. This suggests the Paiwan arrived on Taiwan after ceramic and glass beads were already widely circulated in southeast Asia.
To date, researchers have found no record of the significant technology which would have been required to manufacture beads on the island. So it seems unlikely that the beads of Paiwan royalty would have been manufactured on Taiwan. Others offer that the Paiwan beads came from Europe as archaeological records increasingly suggest early exchange between Europe and Southeast Asia. The beads may also have been a currency of trade with European merchants during early colonial expansion as researchers have noted aborigine cultures in northern Borneo that have similar beads. This would suggest that the Paiwan may be descendants of Borneo aborigines, who may have carried glass beads with them across the oceans arriving in Taiwan between the 13th and 15th centuries AD.
Alternatively, Paiwan glass beads may have had their origin in Holland. The Dutch possess similar bead designs and scholars have recorded oral Paiwan histories relating that the glass beads came from the "Balaca" - a Paiwan name for the Dutch who occupied Taiwan in the seventeenth century. There are Dutch records of trade with Taiwan aborigines at the time specifically noting ceramic and glass beads. Whatever their mysterious origin, the beads that Paiwan nobility have passed down through the generations were not made in Taiwan and the technique of their manufacture was lost or unknown to the Paiwan.

The paragraphs above from: http://indigenous.pristine.net/perspectives/umass/index_en.html

Other links:
http://kinghousewares.blogspot.com/2013/06/legends-behind-paiwan-ceramic-beads.html

http://tribe-asia.com/index.php?option=com_zwin_combo&act=featurearticlesshow§ion=2&catid=20&itemid=221

http://culture.teldap.tw/culture/index.php?option=com_content&id=805