First of all, thank you for this library!
I spotted an odd behaviour recently, though.
Parsing Salesforce Metadata WSDL (https://raw.githubusercontent.com/developerforce/Force.com-Toolkit-for-PHP/master/soapclient/metadata.wsdl.xml) gives pretty much data, but a list of available operations is empty.
This seems to be incorrect. The same file parsed with Ruby's wasabi SOAP library gives a correct list.