configure invoice system and modify template in WHMCS5

Hello, we have our whmcs system, and we need some work to be done. We have two tipes invoices (proforma, and final invoice ) and we need to get the invoice system fully configured and customized with a design of our own. Whmcs does most of it. Therefore there has to be a template customization that will match our provided design ( mostly table oriented, nothing fancy ) Template for proforma will contain some text and when paid, te proforma will transform in a actual invoice. the design for the final invoice shold match something like: [login to view URL] but we will provide detailed info