Mendix supports WSDL 1.1 and SOAP 1.1 and 1.2. Within WSDL multiple styles exists:
For a full explanation of these styles see this article. Mendix supports RPC/encoded, RPC/literal, and Document/literal.
I don't know the exact ones but, Soap and WSDL are currently supported, REST-style webservices are currently not available. See the wiki page here
For everybody who wants to know how to call webservices please follow Howto: Webservices how to page.