Reversal mechanism

We are doing a painting work in our premises. Vendor belongs to composition scheme he is supplying a material with labour for painting work, then is it he has to raise the invoice along with vat @ composition rate, + ST on labour charges @ which portion, My question is what is 01. Vat rate, Service Tax rate, 02. He is an composition dealer then is it we have to pay the ST on reversal mechanism of Works contract. 03. Is it they have to raise invoice alongwith ST+ Vat.