Firefox 3.6.13 configuration for spnego authentification - firefox3.6

Question

I'd like to access to a web application which requires spnego authentification.
This application is running on a network on which i'm connected by VPN connection. Proxy not used.
It works fine under IE6/7/8, Chrome but not firefox 3.6.13
The matter on firefox is: I don't have the prompt message box to enter username and password
To configure my FF, i applied the following instructions, adding the domain name to the trusted and delegation uris fields.
Trying to access to the application, i get the following error message:
A browser did not respond to authentication challenge sent by a server.
Most probably your browser is not configured properly to handle SPNEGO authentication challenge or does not support SPNEGO.
Please, contact your System Administrator to deal with the problem.
Using TCPMon to get an overview of the informations received:
GET /AppName HTTP/1.1
Host: app.domain:8182
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 ( .NET CLR 3.5.30729; .NET4.0E)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: fr,fr-fr;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Cookie: JSESSIONID=6E058E24D9E1873C80B14C56EC59B1E4
GET /AppName/ HTTP/1.1
Host: app.domain:8182
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 ( .NET CLR 3.5.30729; .NET4.0E)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: fr,fr-fr;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Cookie: JSESSIONID=6E058E24D9E1873C80B14C56EC59B1E4
GET /AppName/logon HTTP/1.1
Host: app.domain:8182
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 ( .NET CLR 3.5.30729; .NET4.0E)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: fr,fr-fr;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Cookie: JSESSIONID=6E058E24D9E1873C80B14C56EC59B1E4
HTTP/1.1 302 Déplacé Temporairement
Server: Apache-Coyote/1.1
Location: http://app.domain:8182/AppName/
Transfer-Encoding: chunked
Date: Tue, 14 Dec 2010 16:16:28 GMT
0
HTTP/1.1 302 Déplacé Temporairement
Server: Apache-Coyote/1.1
X-Powered-By: Servlet 2.4; JBoss-4.2.3.GA (build: SVNTag=JBoss_4_2_3_GA date=200807181417)/JBossWeb-2.0
Location: http://app.domain:8182/AppName/logon
Content-Type: text/html
Content-Length: 0
Date: Tue, 14 Dec 2010 16:16:28 GMT
HTTP/1.1 401 Non-Autorisé
Server: Apache-Coyote/1.1
Pragma: No-cache
Cache-Control: no-cache
Expires: Thu, 01 Jan 1970 01:00:00 CET
WWW-Authenticate: Negotiate
Connection: close
Content-Type: text/html
Transfer-Encoding: chunked
Date: Tue, 14 Dec 2010 16:16:28 GMT
4b9
I've checked for the other browsers and i got the same informations.
Do someone have an idea why FF can't interprete it, prompt a dialog box or enter the application ?
Thanks in advance for any help.
Best regards.