Hello, Salvadori.

Try this (I shortened my code, and changed values, so haven't tested this, but should work, as a sample):

Code:
Handle hoHttp
Boolean iSuccess
String sTemp1 sUrlEndpoint sXML

// If necessary, move your own content to the SOAP. Else, use your proper way to get the SOAP to send.
Move "Move '<?xml version="1.0" encoding="utf-8"?>' to sXML
Append sXML '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">'
Append sXML '<soapenv:Header>'
Append sXML '</duae:DuaServiceHeader>'
Append sXML '</soapenv:Header>'
Append sXML '<soapenv:Body>'
Append sXML '<bla bla bla></bla bla bla>'
Append sXML '</soapenv:Body>'
Append sXML '</soapenv:Envelope>'

Move "https://yourwebservice.com/yourservice.asmx" to sUrlEndpoint

Get Create (RefClass(cComChilkatHttp)) To hoHttp
If (Not(IsComObjectCreated(hoHttp))) Begin
    Send CreateComObject of hoHttp
End

//  Set the certificate to be used for mutual TLS authentication
//  (i.e. sets the client-side certificate for two-way TLS authentication)
Get ComSetSslClientCertPfx Of hoHttp "c:\myClientSideCertWithPrivateKey.pfx" "pfxPassword" To iSuccess
If (iSuccess <> True) Begin
    Get ComLastErrorText Of hoHttp To sTemp1
    Showln sTemp1
    Procedure_Return
End

//  Note: The certificate used for the client-side of TLS mutual authentication
//  must have the associated private key available. (PFX files typically store both
//  the certificate and associated private key.)

//  At this point, the HTTP object is setup with the client-side cert, and any SSL/TLS
//  connection will automatically use it if the server demands a client-side cert.

//  The PostXml method may be called to send the XMLHttpRequest
//  using the "POST" HTTP method (also known as "verb").    
Get ComPostXml of hoHttp sUrlEndpoint sXML "utf-8" to vResponse
If (IsComObject(vResponse)) Begin
    Get Create (RefClass(cComChilkatHttpResponse)) to hoResponse
    Set pvComObject of hoResponse to vResponse
End
If (IsNullComObject(vResponse)) Begin
    Get ComLastErrorText of hoHttp to sTemp1
    // Destroy your handles
    Showln sTemp1
    Procedure_Return
End

//  Examine the Body of the HTTP response
//  This would be the XML response sent by the server.
Get ComBodyStr of hoResponse to sXML
        
Send Destroy of hoResponse
Send Destroy of hoHttp
Regards.