Reactivity of thiosemicarbazide

How to form Schiff's Base at both the ends of the thiosemicarbazide? $$\ce{NH2}$$ of hydrazine part reacts easily to form Schiff's base i.e. imine. But $$\ce{NH2}$$ attached to $$\ce{C=S}$$ does not. How to do that?
One approach is by using NCS but that forms imine at $$\ce{NH2}$$ attached to $$\ce{C=S}$$ only and not at the other end.

• (thio)amides have extremely low nucleofility, I think it is impractical to try for the shiff base you want directly, it better to try inderect approach – permeakra Jun 10 '14 at 5:12
• I have read papers which say thioamide is more reactive than amides. Could you suggest any indirect methods? – user 24 Jun 11 '14 at 2:23