If vbadvanced in redirecting you back to a non www link after trying to login, then you need to post at vbadvanced forums and rectify the issue.
Ie if your logging in at your site
www.yourdomain.com and after clicking login it directs you to yourdomain.com, then that is a issue within vbadvanced and needs to be corrected, that is not a reason to use a redirect script to correct and issue with a program.
Also note to make sure your URL settings in the admincp are set correctly, if it already contains the www in the address, then there is another issue as all the links on your site that are in your forums program contain the right links already and nobody will get redirected to a non www link unless they manually type in the address.