All elements in SOAP have a nillable attribute that is set to true. You should be sure to handle this appropriately, depending on the programming language you are using.
For example, if using C#, you will get the type "int?". You should change this to "int" when using the variables. E.g.:
Soap_Response_LicenseOrder RLO = c.GetLicenseOrderTemplate(L.token, (int) PL.result_array[0].ProductTemplates[0].id);
Java handles elements with the type int and the attribute nillable set to true by changing it to an instance of class Integer.