This presentation by Axway at the OASIS Open Standards forum references a large scale deployment of ebXML Messaging in Asia.  The exchange of customs documents between Thailand and the Philippines uses ebXML Messages. 

Via service providers, this link connects many  thousands of exporting and importing companies.  

http://events.oasis-open.org/home/sites/events.oasis-open.org.home/files/Rizk.pdf