Mr. Ampuan Situmeang founded KHAS in year 1992. He has started his practices since year 1988. He has registered Mediator at Batam District Court since year 2004 and as Industrial Relation Arbitrator since year 2006. He sits as Expert for Legislative and ever get involved as Law Expert For Region. He is also ever served as Coordinator of Consultations or Legal Counsel at The bureau of Consultation and Legal Aid of Real Estate of Indonesia (REI) for Batam City. He is now a Permanent Lecturer at Batam International University.
IKADIN Batam (Indonesian Advocates Unity), as Batam Branch Chairman, period of 2003 to 2006, period of 2006 to 2009, period of 2009 to 2012.
PERADI Batam City (Indonesian Bar Association), as Vice Chairman, period of 2009 to 2012.
KADIN Riau Islands Province (Chambers of Commerce and Industry), as Vice Chairman of Law Section and Ethic of Bussiness, period of 2010 to 2015.
APINDO Riau Islands Province (Indonesia Business Association), as Chairman of the Consulting Section, Legal Advocacy, Wages and Public Relation, period of 2009 to 2014.
PGI Riau Islands Province (Indonesia Churces Fellowship), as Chairman II of Operational Bureau, period of 2010 to 2015.
FKUP Batam (Religious Harmony Forum), as Chairman I, period of 2011 to 2016.
BKAG Batam (Batam City Church Cooperation Agency), as Advisor, period of 2012to 2016.