Add new lead in marketo using SOAP API

Hello there,
                  Please tell me how can i add new lead to marketo using SOAP API ? As i am updating my own record(Lead) that inserted directly from marketo using SOAP API but can not Add New Lead.
                  i am implementing my code using : http://ahmeddirie.com/technology/web-development/marketos-updated-soap-php-client-and-the-new-way-to-submit-leads/. i can update my lead using Email address that stored already but if i am passing new Email address OR leadid= 0 it will not stores new lead in to marketo.