Thank you for the hint,
It seems to work (for the first page) but in fact it leads to some errors... You added "/" to "proxy_pass http://localhost:8080/myapp". But I ommitted it after having seen that it leads to the following mistakes on the tomcat side :
The requested resource (/dev01-portal//j_spring_security_check) is not available.
The access log is :
[27/May/2011:18:23:32 +0200] "POST /dev01-portal/j_spring_security_check HTTP/1.1" 404 441 "http://dev01-portal.appssalon.com/" "Mozilla/5.0
I don't know why but it seems it requests http://localhost:8080/dev01-portal//j_spring_security_check.
Do you know where it comes from ?
Thanks again for the help