WSDL data validation in registration in a Wordpress website

I have a running website on the address [login to view URL] .. There's a registration plugin, which works perfectly, but we need to extend on it. The registration, as of now, works this way: the user comes to the site, fills in username, password, email and then he's registered. I call that the first layer of registration. We need to create a SECOND LAYER of registration, so that the registration doesn't end after the user fills in username, password and email, but continues to the next stage, which is WSDL validation. The site asks the user for CARD NUMBER and PINCODE, both of which are validated through the WSDL I will provide you with. Then and only then, after he fills in username, password, email and his CARD NUMBER and PINCODE are validated, we add him to our user database. Each user has a different card number and pincode - each user is given a card, physically. Before they make the card, they fill it in to the external database that's connected to the WSDL. We don't have access to that database, only through the WSDL methods. Once the user fills it in when registrating and we validate it, we just note the card number and "cross it off" so nobody uses that card number again. We also have to display the card number in the backend on the user profile. We're going to be using this WSDL: [login to view URL] Take a look at the methods. You should use PHP with Soap (whatever version you prefer) in order to use these methods and validate the user input. I can give you a detailed description of the methods in the WSDL if you need that.