Configuring a Apache Reverse Proxy for OracleAS Portal and OracleAS Single Sign-On

Question

I'm trying to implement my Oracle Portal 10g Release 2 with a reverse proxy (Apache 2.2) as described in this link: http://download.oracle.com/docs/cd/B14099_19/core.1012/b13998/variants.htm#BEIFECEH without success. I have Oracle Portal, Oracle SSO,OID in the same domain and Apache Reverse Proxy in another domain. Has anyone had success using OracleAS Portal with a reverse proxy?

First of all i'm trying to configure a reverse proxy only for Ora SSO (infra tier). Here is what i already do:

APACHE REVERSE PROXY (Apache 2.2)
http:/proxy.mycompany.com:80

ProxyRequests off
ProxyPassInterpolateEnv On

ProxyPass / http:/portal.tech.everett.it:7777/
ProxyPassReverse / http:/portal.tech.everett.it:7777/
ProxyPreserveHost On

ORACLE SSO
http:/portal.mycompany.com:7777
Here are the steps i already do:

1- CONFIG OID
create an ldif file called setdasurl.ldif and insert as follow:
dn:cn=OperationURLs,cn=DAS,cn=Products,cn=OracleContext
changetype: modify
replace: orcldasurlbase
orcldasurlbase: http:/proxy.mycompany.com/

then do ldapmodify as follow:
ldapmodify -x -h portal.mycompany.com -p 3060 -D "cn=orcladmin" -w password1 -v -f setdasurl.ldif

2- CONFIG ORA SSO (as gentjan user)
export ORACLE_HOME=/home/gentjan/product/10.1.2/OracleAS/infra/

2.1-config Apache config of ORA SSO
vi $ORACLE_HOME/Apache/Apache/conf/httpd.conf

change from:
ServerName portal.mycompany.com
Port 7777
KeepAlive On

to:
ServerName proxy.mycompany.com
Port 80
KeepAlive Off

and add at the end of httpd.conf
RewriteEngine On
RewriteOptions inherit

2.2- update DCM Repository (as root)
$ORACLE_HOME/dcm/bin/dcmctl updateconfig -ct HTTP_Server -v -d

2.3- modify SSO Server Home URL to reverse proxy hostname and port (as root)
$ORACLE_HOME/sso/bin/ssocfg.sh http proxy.mycompany.com 80

2.4- Updating the targets.xml File

Open the ORACLE_HOME/sysman/emd/targets.xml file and locate the target type oracle_sso_server.

vi $ORACLE_HOME/sysman/emd/targets.xml

Update the HTTPMachine and HTTPPort attributes with the proxy server host and port attributes that were passed to ssocfg. For example:
Property NAME="HTTPMachine" VALUE="proxy.mycompany.com"
Property NAME="HTTPPort" VALUE="80"
Property NAME="HTTPProtocol" VALUE="http"
Save and close the file.
Reload the Application Server Control Console by issuing this command (as gentjan):
$ORACLE_HOME/bin/emctl reload

2.5- Re-register mod_osso on SSO Middle-tier with reverse proxy hostname and port

some needed permissions
chmod -R 775 /home/gentjan/product/10.1.2/OracleAS/infra/dcm/

Re-register mod_osso (as gentjan)
$ORACLE_HOME/sso/bin/ssoreg.sh -oracle_home_path /home/gentjan/product/10.1.2/OracleAS/infra -site_name infra.proxy.mycompany.com -config_mod_osso TRUE -mod_osso_url http:/proxy.mycompany.com:80 -update_mode MODIFY

2.6- update DCM Repository (as root)
$ORACLE_HOME/dcm/bin/dcmctl updateconfig -ct HTTP_Server -v -d

2.7- Restart OC4J_Security and Oracle HTTP Server at Infrastructure tier
$ORACLE_HOME/opmn/bin/opmnctl restartproc process-type=HTTP_Server
$ORACLE_HOME/opmn/bin/opmnctl restartproc process-type=OC4J_SECURITY

After this modifications my reverse proxy is ok.
I can access to http:/proxy.mycompany.com:80 and this redirect me to Oracle Application Server Welcome page.
If i try http:/proxy.mycompany.com/pls/orasso/orasso.home, i can view the SSO Server Home page.
The problem that i find is when i click to Login page for Oracle SSO.
I have the following error:

Forbidden You don't have permission to access /pls/orasso/ORASSO.wwsec_app_priv.login on this server.

So, in other words I can't do the login/logout under reverse proxy. Anyone can help?