Issue with parsing a form variable of a HTTP POST request

Hi everyone, 

I am currently sending an HTTP POST request to an EnsLib.HTTP.Service service (which has an EnsLib.HTTP.InboundAdapter associated). 

Here the request URL: http://10.41.11.210:57772/csp/healthshare/dce/POSTServiceClass.cls?rpyTo...

From the documentation I have read (https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=EHTTP_inbound) I get that the form variables are written into the request body in case of a POST. I have also implemented the OnInint() is this way to enable the form variables parsing: 

Method OnInit() As %Status
{
    Set ..Adapter.ParseBodyFormVars=1
    Quit 1
}

The OnProcessImput of the service is implemented in this way: 

Class POSTServiceClass Extends (EnsLib.HTTP.Service, HS.Util.Trace.Helper)
{
Parameter CONTENTTYPE = "text/xml";
Property TargetProcess As %String(MAXLEN = 250) [ Required ]; .
Property isServerFault As %Boolean;
Method OnInit() As %Status
{
    Set ..Adapter.ParseBodyFormVars=1
    Quit 1
}
Method OnProcessInput(pInput As %GlobalCharacterStream, Output pOutput As %GlobalCharacterStream, ByRef pHint As %String) As %Status
{
set ..isServerFault = $$$YES  // Server Fault by default #dim token As %String
if '$isObject(pInput) || (pInput.Size = 0) 
{
set ..isServerFault = $$$NO  
quit $$$ERROR($$$GeneralError, "Null request")
}
#dim inMsg As HS.Message.XMLMessage = ##class(HS.Message.XMLMessage).%New()
set inMsg.ContentStream=pInput
#dim outMsg As HS.Message.XMLMessage = "" 
#dim sc As %Status = ..SendRequestSync(..TargetProcess, inMsg, .outMsg) 
if $$$ISERR(sc) quit sc // check if we have a good response
if '$isObject(outMsg) || 'outMsg.%Extends("HS.Message.XMLMessage") quit $$$ERROR($$$GeneralError, "Null or incorrect response") set pOutput = outMsg.ContentStream
quit $$$OK
}

I was expecting to find my form variable (rpyToken) into the contentStream of the isMsg XMLMessage but there isn't. 

Can someone explain me what is my mistake?

Thank you in advance.