Combine the milk with the lemon juice and set aside.
Combine flour,baking soda,and salt and set aside.
Cream the butter and cream cheese and gradually add the sugar,beating well. Beat in the egg and then add the cocoa and vanilla,blending well. To this mixture,alternately blend in the milk and flour mixtures. Stir in the coconut.
Pour batter into well-greased 9 x 5 x 3-inch loaf pan and bake at 350 degrees for 1 hr, or until tests done. Allow to cool 5-10 minutes in pan and then remove to cake plate. Allow to cool completely before slicing.