Let's consider a character with BAB +6/+1 under the effects of Haste, wielding a greatsword and having a shuriken attached to his belt. Can he make the first attack with the greatsword (BAB +6), then remove one hand from the handle as a free action, throw the shuriken (BAB +6, Haste), wield again the sword 2H and attack again with it (BAB +1)?