Customizing WHMCS user registration form

Customizing WHMCS user registration form We already used WHMCS in its defoult mode, Now we need to modify / customize the user registration form WHMCS. how we wont the form to run: At the customer registration step ( both if the customer wants to only get registered and if the customer is taking an order) When will the user during registration (either in the order that if the user wants to record alone, without effettura order) the user must first select the group of wich he belogs (we have already created the 2 groups in wgmcs) Private or Company and after upon the choice he made he will be directed to the registration form. The two screen shows the two different forms, one for Companies and one fot the Private parties. (the form must be in Italian language as that in the screen) The screen is only illustrative, any graphics needed we'll provide in psd format or other format if required)