Array not received, XML invalid

Hi, I'm sending some associative array throught SOAP and it was received just as sent on php 5.0.4, after upgrade on 5.1.2 (on FreeBSD 6.1) it went wrong. Instead of array I get stuctured stdClass. I dumped soapclient object and in body part of last response I found: ...<return><item><key>vars</key><value><item><key>soapKeyId</key>... There should be some xsd atributes with xsi values as far as I know. Root element seems ok: <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:ns2="http://xml.apache.org/xml-soap" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"> Does anyone have clue what's wrong? Thanks a lot Mirek