Soap web service request from wordpress plugin

I'm developing a wordpress plugin and need to perform soap calls. After understanding that cURL isn't option (manage to run some code in my browser but can't make it work within the plugin), I'm trying to use SoapClient by php5.

the connection seems to be working since i'm able to print out the __getFunctions() var:

StatusResponse Status(Status $parameters)" 
[1]= string(65) "AdministrationResponse Administration(Administration $parameters)" 
[2]= string(74) "FetchPropertyListResponse FetchPropertyList(FetchPropertyList $parameters)" 
[3]= string(77) "FetchPropertyGroupResponse FetchPropertyGroup(FetchPropertyGroup $parameters)" 
[4]= string(74) "FetchPropertyInfoResponse FetchPropertyInfo(FetchPropertyInfo $parameters)" 
[5]= string(98) "FetchPropertyAvailabilityResponse FetchPropertyAvailability(FetchPropertyAvailability $parameters)" 
[6]= string(95) "FetchPropertyRateSummaryResponse FetchPropertyRateSummary(FetchPropertyRateSummary $parameters)" 
[7]= string(86) "FetchStayAvailabilityResponse FetchStayAvailability(FetchStayAvailability $parameters)" 
[8]= string(71) "PlaceReservationResponse PlaceReservation(PlaceReservation $parameters)" 
[9]= string(89) "CheckReservationExistsResponse CheckReservationExists(CheckReservationExists $parameters)" 
[10]= string(74) "CancelReservationResponse CancelReservation(CancelReservation $parameters)" 
[11]= string(56) "PostPaymentResponse PostPayment(PostPayment $parameters)" 
[12]= string(53) "PostChargeResponse PostCharge(PostCharge $parameters)" 
[13]= string(44) "PostEFTResponse PostEFT(PostEFT $parameters)" 
[14]= string(56) "PostMessageResponse PostMessage(PostMessage $parameters)" 
[15]= string(50) "PlaceHoldResponse PlaceHold(PlaceHold $parameters)" 
[16]= string(53) "CancelHoldResponse CancelHold(CancelHold $parameters)" 
[17]= string(62) "ValidateAgentResponse ValidateAgent(ValidateAgent $parameters)" 
[18]= string(68) "ValidateCompanyResponse ValidateCompany(ValidateCompany $parameters)" 
[19]= string(80) "FetchPropertyReportResponse FetchPropertyReport(FetchPropertyReport $parameters)" 
[20]= string(41) "StatusResponse Status(Status $parameters)" 
[21]= string(65) "AdministrationResponse Administration(Administration $parameters)" 
[22]= string(74) "FetchPropertyListResponse FetchPropertyList(FetchPropertyList $parameters)" 
[23]= string(77) "FetchPropertyGroupResponse FetchPropertyGroup(FetchPropertyGroup $parameters)" 
[24]= string(74) "FetchPropertyInfoResponse FetchPropertyInfo(FetchPropertyInfo $parameters)" 
[25]= string(98) "FetchPropertyAvailabilityResponse FetchPropertyAvailability(FetchPropertyAvailability $parameters)" 
[26]= string(95) "FetchPropertyRateSummaryResponse FetchPropertyRateSummary(FetchPropertyRateSummary $parameters)" 
[27]= string(86) "FetchStayAvailabilityResponse FetchStayAvailability(FetchStayAvailability $parameters)" 
[28]= string(71) "PlaceReservationResponse PlaceReservation(PlaceReservation $parameters)" 
[29]= string(89) "CheckReservationExistsResponse CheckReservationExists(CheckReservationExists $parameters)" 
[30]= string(74) "CancelReservationResponse CancelReservation(CancelReservation $parameters)" 
[31]= string(56) "PostPaymentResponse PostPayment(PostPayment $parameters)" 
[32]= string(53) "PostChargeResponse PostCharge(PostCharge $parameters)" 
[33]= string(44) "PostEFTResponse PostEFT(PostEFT $parameters)" 
[34]= string(56) "PostMessageResponse PostMessage(PostMessage $parameters)" 
[35]= string(50) "PlaceHoldResponse PlaceHold(PlaceHold $parameters)" 
[36]= string(53) "CancelHoldResponse CancelHold(CancelHold $parameters)" 
[37]= string(62) "ValidateAgentResponse ValidateAgent(ValidateAgent $parameters)" 
[38]= string(68) "ValidateCompanyResponse ValidateCompany(ValidateCompany $parameters)" 
[39]= string(80) "FetchPropertyReportResponse FetchPropertyReport(FetchPropertyReport $parameters)" }

When i try to call to one of the functions i get an "Object reference not set to an instance of an object." Error. I'm familiar with this error from the time before i manage to send soap request throw POSTMAN chrome plugin. i get this error when the body part was missing details.

this is the request i manage to send from POSTMAN:

soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
                    xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
  soap:Header
    ChannelCredentials xmlns="ChartsWeb"
      Username???/Username
      Password???/Password
    /ChannelCredentials
  /soap:Header
  soap:Body
    FetchPropertyInfo xmlns="ChartsWeb"
      FetchPropertyInfoRequest
        PropertyInfoRequests
          PropertyInfoRequest PropCode="???" MySite="???"/
        /PropertyInfoRequests
      /FetchPropertyInfoRequest
    /FetchPropertyInfo
  /soap:Body
/soap:Envelope

and get the expected result.

this is the current code i get :

?php




$client = new SoapClient("http://stage-chartsweb.chartspms.com.au/webservices/service.asmx?wsdl", array('trace' = 1));

$ns = 'ChartsWeb'; //Namespace of the WS. 

//Body of the Soap Header. 
$headerbody = array('Username' = $username, 
                    'Password' = $password,
                    'LoggingRequest' = True);

//Create Soap Header.        
 $header = new SOAPHeader($ns, 'ChannelCredentials', $headerbody);        

// //set the Headers of Soap Client. 
 $client-__setSoapHeaders($header); 

$fcs = $client-__getFunctions();

$res_FetchPropertyInfo = $client-FetchPropertyInfo(array("PropCode" = $prop_code, "MySite" = $my_site));

var_dump($client-__getLastRequest());

and this is the request it produce:

SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="ChartsWeb"
    SOAP-ENV:Header
        ns1:ChannelCredentials
            ns1:Username???/ns1:Username
            ns1:Password???/ns1:Password
            ns1:LoggingRequesttrue/ns1:LoggingRequest
        /ns1:ChannelCredentials
    /SOAP-ENV:Header
    SOAP-ENV:Body
        ns1:FetchPropertyInfo/
    /SOAP-ENV:Body
/SOAP-ENV:Envelope

it seems like something with my body don't setup correctly..

anyone deal with this problem?