Like this:
<VirtualHost *:8181>
ServerAdmin hostmaster@example.com
ProxyRequests off
DocumentRoot /home/DOMAIN_DIR
ProxyPreserveHost On
ServerName panel.my_domain.com
ServerAlias panel.my_domain.com
<Location />
ProxyPass http://panel.my_domain.com:2030/
ProxyPassReverse http://panel.my_domain.com:2030/
Order allow,deny
Allow from all
</Location>
</VirtualHost>
?
Thanks!