SMS pdu and MIDLet

Hi,

I have some questions (and some trouble) about Wireless Messaging..

On one side I have a MIDlet running on a NOKIA Serie 40 2nd edition which send
sms to a server using a code like :

try {
   String addr = "sms://+2215461418" ;
   MessageConnection conn = ( MessageConnection )Connector.open( addr ) ;
   TextMessage msg = ( TextMessage )conn.newMessage( MessageConnection.TEXT_MESSAGE ) ;
   msg.setPayloadText( toSend ) ;
   conn.send( msg ) ;
   conn.close( ) ;
} catch( Exception e ) {
   e.printStackTrace( ) ;
}

On the other side, I receive (correctly) the SMS on a PC with a Siemens TC45 GSM Modem using AT commands in a java servlet...
Then, the PC need to send SMS to the MIDLet, so I need to use a port for the destination.
Using AT command and PDU coding with mt TC45, I send a PDU like :

0051000781255535F30000AA0A060504411A0000CF25

where 060504411A0000 means destination port 16666

When I send this PDU the MIDlet is supposed to receive it using a code like :

protected void startApp( ) {
...
   try {
      smsconn = ( MessageConnection )Connector.open( "sms://:16666" ) ;
           smsconn.setMessageListener( this ) ;
   } catch( Exception e ) {
      e.printStackTrace( ) ;
   }
...
}

public void notifyIncomingMessage( MessageConnection conn ) {
       try {
          Message m = smsconn.receive( ) ;
      ...
}

For information the JAD looks like :
MIDlet-Name: FREDMidlet
MIDlet-Version: 1.0
MIDlet-Vendor: FRED
MicroEdition-Profile: MIDP-2.0
MicroEdition-Configuration: CLDC-1.0
MIDlet-Jar-URL: FRED.jar
MIDlet-Jar-Size: 22753
MIDlet-Icon: /icone.gif
MIDlet-Push-1: sms://:16666, FREDMidlet, *
MIDlet-Permissions: javax.microedition.io.Connector.sms, javax.wireless.messaging.sms.send, javax.wireless.messaging.sms.receive
MIDlet-1: FREDMidlet, /icone.gif, FREDMidlet
   
The problem is the MIDlet never receive the SMS.
For information, if I change the PDU to :

0051000781255535F30000AA0A06050415810000CF25

where 06050415810000 means destination port 5505 which is the 'ringtones supply' port. In this case, the phone corectly
receive the notification of incomming ringtone, which means (for me) the sended pdu is good, so the problem is on the MIDlet side...

For information I try to take a look at the PushRegistry and try PushRegistry.listConnections( true ) the result is always null
because the MIDlet had never been setup for wake on receive... If try PushRegistry.listConnections( false ) I have the only entry "sms://:16666"

Q: Is an operator can filter ports to not allow other ports than well-known one ?
Q: Is my architecture right ?
Q: If the MIDLet send the SMS on a destination port, how the TC45 receive it ?
Q: What is the fonction of the 'source port' in PDU ? (except for information...)
Q: Any suggestions?

TIA
FRED