applet et proxy

bonjour,

je developpe actuelement une applet qui a pour principal tache d'upload des fichiers d'un poste client vers un serveur ISS en mode https.

pour cela j'utilise la la librairie httpClient de jakarta et principalement la methode methodPost().

mon applet fonctionne correctement lorsque le poste client ne se trouve pas derriere un serveur proxy. En revanche si un serveur proxy est présent la connexion(client.executeMethod(...)) échoue.

java.net.UnknownHostException: www.mon-site.fr
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.<init>(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketFactoryImpl.createSocket(Unknown Source)
at org.apache.commons.httpclient.protocol.SSLProtocolSocketFactory.createSocket(SSLProtocolSocketFactory.java:81)
at org.apache.commons.httpclient.protocol.SSLProtocolSocketFactory.createSocket(SSLProtocolSocketFactory.java:126)
at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:706)
at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.open(MultiThreadedHttpConnectionManager.java:1321)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:386)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:170)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:396)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:324)
at appletinterbat.upload.WebClient.upload(WebClient.java:233)
at appletinterbat.applet.ui.MainPanel.mkUpload(MainPanel.java:319)
at appletinterbat.applet.ui.MainPanel.access$400(MainPanel.java:47)
at appletinterbat.applet.ui.MainPanel$2.run(MainPanel.java:202)
at foxtrot.AbstractWorkerThread$1.run(AbstractWorkerThread.java:39)
at java.security.AccessController.doPrivileged(Native Method)
at foxtrot.AbstractWorkerThread.runTask(AbstractWorkerThread.java:35)
at foxtrot.workers.SingleWorkerThread.run(SingleWorkerThread.java:196)
at foxtrot.workers.SingleWorkerThread.run(SingleWorkerThread.java:179)
at java.lang.Thread.run(Unknown Source)


apparamant il existe des methodes qui permet de traverser le proxy:

Properties props = System.getProperties();
props.put("http.proxyHost", "proxyhostname");
props.put("http.proxyPort", "proxyhostport");

Mais comment recuperer "proxyhostname" et "proxyhostport"?

toute aide sera la bienvenue.
Merci.