Different SOAP output for the same software

Hi all! I am facing strange problem with SOAP output generated by the 
same software installed on different servers. And I am not sure why 
this happens.

I am trying to access with Apache Axis SOAP client two different 
installations of Magento store of the same version 1.3.2.4.

When accessing one installation from I am getting SOAP response in 
format which Axis client understand well:

<SOAP-ENV:Envelope 
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" 
xmlns:ns1="urn:Magento"
                        
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
                        xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
         <SOAP-ENV:Body>
             <ns1:salesOrderListResponse>
                 <result SOAP-ENC:arrayType="ns1:salesOrderEntity[24]" 
xsi:type="ns1:salesOrderEntityArray">
                     <item xsi:type="ns1:salesOrderEntity">
                         <increment_id 
xsi:type="xsd:string">100000056-1</increment_id>
                         <parent_id xsi:type="xsd:string">0</parent_id>  

When I am trying to access another server with the same Magento version 
installed I am getting response in another format which uses Map type 
to represent SalesOrderEntity object:

<SOAP-ENV:Envelope 
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" 
xmlns:ns1="urn:Magento"
                   xmlns:ns2="http://xml.apache.org/xml-soap" 
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
                  
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <SOAP-ENV:Body>
        <ns1:salesOrderListResponse>
            <result SOAP-ENC:arrayType="ns2:Map[30]" 
xsi:type="ns1:salesOrderEntityArray">
                <item xsi:type="ns2:Map">
                    <item>
                        <key xsi:type="xsd:string">increment_id</key>
                        <value xsi:type="xsd:string">200000281</value>
                    </item>
                    <item>
                        <key xsi:type="xsd:string">parent_id</key>
                        <value xsi:type="xsd:string">0</value>
                    </item>

Magento forum didn't help. On both servers PHP5 is installed. I am 
wonder what can affect on the output format and how I can fix it. I 
also wonder if Axis client should read both formats correctly, but 
currently I am getting Axis error when connecting to second server: 
ArrayStoreException: HashMap - it looks like the problem is that server 
returns Map type instead of SalesOrderEntity type expected.

I will quite appreciate any ideas.

Thanks,
Vladimir.