difficulties with SOAP client parameters

difficulties with SOAP client parameters

I'm breaking my head on this one and searched ages to find topics that
would point me in the right direction but without luck.
All I need to do is send a couple of parameters for this request, not too
hard. My normal request I do with the php Soap function:
$client = new SoapClient("http://SOAPURL");
$result = $client->__soapCall("FUNCTION", array('PARAMETERS' => 'value'));
But here it comes: In the following wsdl I'm having an issue with the
second parameter Membership. How on earth is my parameter array going to
look like with the values of Membership in it? I seriously tried tons of
variations but none of 'm is giving me success.
<soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:urn="urn:NAMESOAPIntf-INSOAP">
<soapenv:Header/>
<soapenv:Body>
<urn:SC_Insert_Membership
soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<Check_Only xsi:type="xsd:int">0</Check_Only>
<Membership xsi:type="urn:TMembership" xmlns:urn="urn:NSKIVSOAPIntf">
<MEMBERSHIP_AUTOPAYCODE_ID
xsi:type="xsd:string">0</MEMBERSHIP_AUTOPAYCODE_ID>
<MEMBERSHIP_PAYACCOUNT_ID
xsi:type="xsd:string">(number)</MEMBERSHIP_PAYACCOUNT_ID>
<MEMBERSHIP_RELATION_ID
xsi:type="xsd:int">(number)</MEMBERSHIP_RELATION_ID>
<MEMBERSHIP_SOURCE_ID
xsi:type="xsd:string">(number)</MEMBERSHIP_SOURCE_ID>
</Membership>
</urn:SC_Insert_Membership>
</soapenv:Body>
</soapenv:Envelope>
Who can help me?
Thanks for your time.