adding www to the url automatically

Hi guys, i have installed vbseo and eveything is working fine except for one thing

When i enter:
http*//enfoque21.com it takes me to http*//www.enfoque21.com , that's ok, how i wnt it.

But when i enter a thread for example

http*//enfoque21.com/forum/threadname.html
it does not redirect me to www...

How should i configure it ?
I want the www to be always in the url

Thanks in advance

Please see: [How to] Setup www.yourdomain.com or yourdomain.com (www vs. non-www) - With .htaccess 301 redirects - vBulletin SEO Forums

Many thanks brian