The government has appointed international lawyer Rodrigo Oreamuno to arbitrate on its behalf in the Rs. 20,000 crore tax case with the UK telecom major Vodafone. Costa Rica-based Oreamuno replaces former Chief Justice of India RC Lahoti who had in May recused himself. “Rodrigo Oreamuno has been named as the arbitrator from the Indian side,” a source said when asked if the government has decided on a arbitrator in the Vodafone case.