ExactTarget Marketing Cloud seems to have a comprehensive SOAP API and have SDKs in Java, .NET, PHP and Ruby for that. I am wondering if there is a SDK built for Apex. I don't see it available on the documentation. However, since Salesforce has re-branded ExactTarget as Marketing Cloud, I am hoping that someone from the Salesforce expert team should have built an Apex SDK as well.
Because of the nature of the SOAP API's WSDL, we weren't able to use it using the proxy classes generated using WSDL2Apex (especially because of lack of the SOAP header for setting authentication parameter). So, we tried to build the SOAP message directly and POST it to the end point. Now, we are facing issues with calling the method that adds subscribers to the subscriber list. Any help on this is greatly appreciated.