Delphi SOAP Request - web-services

Question

I'm trying to send a SOAP Request to a webservice in Delphi XE5. Actually there is a WSDL available which I imported via WSDL Importer. I established a connection to this webservice with the components THTTPRIO (rio) and IdEncoderMIME1 for the HTTP Authentication Request.
The SOAP Request was build via TXMLDocument and has the following structure:
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:cod=NS_Codelist>
<soapenv:Header/>
<soapenv:Body>
<cod:GetLatestChangeDatesRequest>
<!--Zero or more repetitions:-->
<CodeListID>1035</CodeListID>
</cod:GetLatestChangeDatesRequest>
</soapenv:Body>
</soapenv:Envelope>
Furthermore I received the Porttype of the webservice.
codeserv:= GetCodeListPortType(true,'',rio);
These are methods from the WSDL:
codeserv.GetLatestChangeDates(const body:GetLatestChangeDatesRequestType):GetLatestChangeDatesResponseType
GetLatestChangeDatesRequestType = array of Int64;
GetLatestChangeDatesRequest = GetLatestChangeDatesRequestType;
GetLatestChangeDatesResponseType = array of CodeListLatestChangeDateType;
GetLatestChangeDatesResponse = GetLatestChangeDatesResponseType;
CodeListLatestChangeDateType
property CodeListID: Int64
property LatestChangeDate: TXSDate
I have already tried to set an array of Int64 for the parameter but then it says "element CodeListID is missing".
Unfortunately I don't find a way to send this XML SOAP Request to the webservice and to receive the response. Any ideas?
EDIT: I have tried to use the WSDL methods
var
codeserv: CodeListPortType;
arrIDs: GetLatestChangeDatesRequest;
response: GetLatestChangeDatesResponse;
begin
codeserv:= GetCodeListPortType(true,'',rio);
SetLength(arrIDs,1);
arrIDs[0]:= 1035;
response:= codeserv.GetLatestChangeDates(arrIDs);
But then I receive the following error message: 'invalid content was found starting with element 'long'. One of '{CodeListID}' is expected.'
In the SOAP Request there have to be the element CodeListID. Unfortunately it seems the method GetLatestChangeDates isn't creating the elements in the SOAP Request. The SOAP Request posted above should have been created with this method (hopefully).