Vat registration for works contract

Dear Colleauge,

One of my friend wants to register his proprietory business under MVAT act. According to the business activity he explained to me i told him to register under works contract composition scheme.

My question is, whether he can get registration under the aforesaid activity Voluntary/mandatory?

If mandatory then he need to show the invoice pertaining to goods only or both( goods & service) and in order to compute the threshold limit of Rs.5lac. it cover only goods related item or both i.e. (goods& service)?

Please guide me.

Thank you.