In Freenas version 0.72... a query for the named method returns 'Unknown method'. I've tried other methods and runs ok.
Example:
-Query-
<?xml version="1.0"?>
<methodCall>
<methodName>system.getInfo</methodName>
</methodCall>
-Answer-
<?xml version="1.0"?>
<methodResponse>
<fault>
<value>
<struct><member><name>faultCode</name>
<value><int>1</int></value>
</member>
<member>
<name>faultString</name>
<value><string>Unknown method</string></value>
</member>
</struct>
</value>
</fault>
</methodResponse>
Other methods... like 'system.listMethods' run fine.
-Query-
<?xml version="1.0"?>
<methodCall>
<methodName>system.listMethods</methodName>
</methodCall>
-Answer-
<?xml version="1.0"?>
<methodResponse>
<params>
<param>
<value><array>
<data>
<value><string>system.getInfo</string></value>
<value><string>system.listMethods</string></value>
<value><string>system.methodHelp</string></value>
<value><string>system.methodSignature</string></value>
<value><string>system.multicall</string></value>
<value><string>system.getCapabilities</string></value>
</data>
</array></value>
</param>
</params>
</methodResponse>