Who administers direct democracy mechanisms at the national level?

Constitution (2011)http://www.sudantribune.com/IMG/pdf/The_Draft_Transitional_Constitution_of_the_ROSS2-2.pdf

Article 195 (3)The Commission shall perform the following functions: (a) prepare the general electoral roll and pursue its annual revision; (b) organize and conduct general elections, by-elections, and local elections in accordance with this Constitution and the law; (c) organize and conduct any referendum in accordance with this Constitution and the law; (d) perform any other relevant function as may be prescribed by law.

Southern Sudan Referendum Act 2009http://saycsd.org/doc/SouthernSudanReferendumActFeb10EnglishVersion.pdf