Example of creating a SOAP controller for handling both WSDL and SOAP requests in ZF2.

module.config.php

<?php
return array(
    'router' => array('routes' => array(
        'soap' => array(
            'type' => 'Literal',
            'options' => array(
                'route' => '/soap',
                'defaults' => array(
                    'controller' => 'Soap\Controller\SoapController',
                    'action' => 'soap',
                ),
            ),
        ),
    )),
    'service_manager' => array(
        'factories' => array(
            'Soap\Controller\SoapController' => 'SomeFactoryYouWillNeedToWrite',
        ),
    ),
);

SoapController.php

<?php

namespace Soap\Controller;

use Zend\Mvc\Controller\AbstractActionController;
use Zend\Soap\AutoDiscover as SoapWsdlGenerator;
use Zend\Soap\Server as SoapServer;

class SoapController
{
    protected $route;

    protected $soap;

    protected $wsdlGenarator

    public function __construct($route, SoapServer $soapServer, SoapWsdlGenerator $wsdlGenerator)
    {
        $this->route = $route;
        $this->soap = $soapServer;
        $this->wsdlGenerator = $wsdlGenerator;
    }

    public function soapAction()
    {
        $request  = $this->getRequest();
        $response = $this->getResponse();

        switch ($request->getMethod()) {
            case 'GET':
                $this->wsdlGenerator->setUri($this->url($this->route));
                $wsdl = $this->wsdlGenerator->generate();
                $response->getHeaders()->addHeaderLine('Content-Type', 'application/wsdl+xml');
                $response->setContent($wsdl->toXml());
                break;

            case 'POST':
                $this->soap->setReturnResponse(true);
                $soapResponse = $this->soap->handle();
                if ($soapResponse instanceof SoapFault) {
                    $soapResponse = (string) $soapResponse;
                }

                $response->getHeaders()->addHeaderLine('Content-Type', 'application/xml');
                $response->setContent($soapResponse);
                break;

            default:
                $response->setStatusCode(405);
                $response->getHeaders()->addHeaderLine('Allow', 'GET,POST');
                break;
        }

        return $response;
    }
}

Notes:

• You'll need to create a factory for the SoapController that will inject the appropriate route name ("soap" in this case), a Zend\Soap\Server instance, and a Zend\Soap\AutoDiscover instance. There are examples of setting those up in the manual.
• I'm not 100% sure the fault response will be done correctly with this, but reasonably sure.

class SoapController should be class SoapController extends AbstractActionController.

There are some more typos, but it works!!!

Thank you, @weierophinney

You can use 'method' type child-routes to route the request to different controller actions to handle GET and POST instead of handling them both in the same action

<?php

return array(
    'router' => array('routes' => array(
        'soap.test.route' => array(
            'type' => 'literal',
            'options' => array(
                'route' => '/soaptest',
            ),
            'child_routes' => [
                'get' => [
                    'type' => 'method',
                    'options' => [
                        'verb' => 'get',
                        'defaults' => [
                            'controller' => 'SoapTest\Controller\SoapTestController',
                            'action' => 'get'
                        ],
                    ],
                ],
                'post' => [
                    'type' => 'method',
                    'options' => [
                        'verb' => 'post',
                        'defaults' => [
                            'controller' => 'SoapTest\Controller\SoapTestController',
                            'action' => 'post'
                        ],
                    ],
                ],
            ],
        ),
    )),
    'controllers' => array(
        'invokables' => array(
            'SoapTest\Controller\SoapTestController' => 'SoapTest\SoapTestController',
        ),
    ),
);