I'm calling SOAP functions from C#. I request a list of users. This was working fine in my early tests, but now that I have 160+ users, I get an exception that:
An unhandled exception of type 'System.ServiceModel.CommunicationException' occurred in mscorlib.dll
Additional information: The maximum message size quota for incoming messages (65536) has been exceeded. To increase the quota, use the MaxReceivedMessageSize property on the appropriate binding element.
In the link you've posted, the XML configuration in question appears to be the WCF binding information. This information should be embedded within the app.config or web.config of your client application.
Look for the <system.serviceModel> section.