proxy settings in plesk server

proxy settings in plesk server

Actually I am installing the Java script in plesk server
I have installed the tomcat /usr/local/tomcat6/webapps and i deployed the
script successfully but when I access my domain domainname.com it is
showing apache default page
So for that I have edited my conf file in this path
/var/www/vhosts/domainname/conf/13777576500.44543900_httpd.include
ProxyPreserveHost On SuexecUserGroup "proma" "psacln"
ServerAdmin "test@gmail.com"
DocumentRoot "/var/www/vhosts/domainname/httpdocs"
ProxyPass / http://ipaddress:8080/ ProxyPassReverse / http://ipaddress:8080/
After that I restarted the server and site is pointing to tomcat and
script working perfectly.
If again I restarted the server then the conf file is override and all the
changes I have made is lost
I tried to create the vhost.conf file but that also not working.
Please help me