Working with WSDL Files

If you do not upload a WSDL file, Salesforce module will use a default .wsdl file (salesforce_api/toolkit/soapclient/enterprise.wsdl.xml), which may not be compatible with your organization's Salesforce installation or the current Salesforce API. It is highly recommended that you supply your own Enterprise WSDL file via the WSDL administration panes at admin/settings/salesforce and admin/settings/salesforce/wsdl. These panes will walk you through creating a directory outside your webroot and uploading the WSDL file to that directory.

When switching between WSDL files, keep in mind that PHP's SoapClient is caching WSDL information. Though PHP's SOAP WSDL cache should be cleaned when you upload a new WSDL file, you can permenantly disable caching of WSDL information by adding this line to your settings.php:

ini_set('soap.wsdl_cache_enabled', '0');

You can control the life time of your cache by adding this line to your settings.php:

ini_set('soap.wsdl_cache_ttl', '0');

For more information on SoapClient refer to http://php.net/manual/en/book.soap.php