Sending Arabic SMS messages in the channel

I am trying to send Arabic sms (or French sms) from kannel and it does not reach the end of the client (somtimes ?????? for Arabic words), after some analysis of the values ​​sent between bearebox, smsbox and smsc, I found out that an encoding error occurs between my bear box and smsbox.

I used charset=utf-8&coding=2sms in my HTTP request, but the same problem occurs

Does anyone have any ideas on what is the problem or the best solution?

here is the code i use to send sms

StringBuffer param = new StringBuffer()
       param.append("http://localhost:1025/cgi-bin/sendsms?")
       param.append(URLEncoder.encode("username","UTF-8")).append("=").append(URLEncoder.encode("xxx","UTF-8"))
       param.append("&").append(URLEncoder.encode("password","UTF-8")).append("=").append(URLEncoder.encode("xxxx","UTF-8"))
       param.append("&").append(URLEncoder.encode("to","UTF-8")).append("=").append(URLEncoder.encode(numTel,"UTF-8"));
       param.append("&").append(URLEncoder.encode("charset","UTF-8")).append("=").append(URLEncoder.encode("utf-8","UTF-8"))

       param.append("&").append(URLEncoder.encode("coding","UTF-8")).append("=").append(URLEncoder.encode("2","UTF-8"))
       param.append("&").append(URLEncoder.encode("text","UTF-8")).append("=").append(URLEncoder.encode(text,"UTF-8"))
       param.append("&").append(URLEncoder.encode("priority","UTF-8")).append("=").append(URLEncoder.encode(""+priority,"UTF-8"))
       param.append("&").append(URLEncoder.encode("dlr-mask","UTF-8")).append("=").append(URLEncoder.encode("31","UTF-8"))
       param.append("&").append(URLEncoder.encode("dlr-url","UTF-8")).append("=").append(URLEncoder.encode(urlString,"UTF-8"))
       try{
           URL url = new URL(param.toString())
           System.out.println("INFO : Opening connection ")
           HttpURLConnection urlconnection = (HttpURLConnection) url.openConnection()
           System.out.println("INFO : Connection openned")
           BufferedReader input = new BufferedReader( new InputStreamReader(urlconnection.getInputStream()))
           String inputLine

           while ((inputLine = input.readLine()) != null)
               aResult.append(inputLine)
           input.close()
       }catch(Exception e){
           e.printStackTrace()
           return false
       }

       System.out.println("response : "+aResult.toString())
       System.out.println("INFO : all sent disconnect.")
'

thank