Named callbacks appear to work fine.

test.js

async.map( ['A', 'B', 'C' ],
	function( item, cb ) {
		console.log( item );
		cb( null, '' + item + item );
	},
	function( error, results ) {
		console.log( 'results: ' + require( 'util' ).inspect( results ) );
	});

async.map( ['A', 'B', 'C' ],
	function it( item, cb ) {
		console.log( item );
		cb( null, '' + item + item );
	},
	function cb( error, results ) {
		console.log( 'results: ' + require( 'util' ).inspect( results ) );
	});