Apache Tomcat Reverse Proxy Howto

Apache & Tomcat: ProxyPass and ProxyPassReverse

I'am having troubles configuring Apache and Tomcat, this is the scenario:

I have an Apache Web Server, running and working normally, I can access to this one just typing:

Also, in this host, I have a Tomcat running and working fine; I've created a mini web-app which files are inside "prueba" directory, I can access typing:

(I know that Apache is running in 80 port and Tomcat in 8080)

What I want to do is that througt Apache an user can access to 'pruebas' (running on Tomcat), I mean:

I've readen a lot of this, and I think that there are 2 ways to do this, and I've decided enabling the proxy modules (proxy and proxy_ajp, with a2enmod), also I've readed I must edit this file: sites-available / default, this is the content:

But this hasn't work propperly :(

I have to say that I've tried whit many changes, ont this 2 lines, like:

or

(each time I edit the file, I restart apache)

But when I access to [http: // localhost / prueba /], I have: Service Temporarily Unavailable

Has anyone knows why? Thanks in advance guys.

Pd: I'm working with apache 2.2.17 and tomcat6.