[bridge2heyday]

The Question is not clear enough .. But I guess you have VBSEO installed with the first URL Scheme and you want to convert to Basic Vbulletin Friendly URLs and Make Old URLs (indexed or linked ) redirect to new URLs ( don't give 404 ) ..
If this is the case .. you can
- Uninstall VBSEO
- Go to Admincp -> settings -> Options -> Friendly URLs -> URL Type -> Basic Friendly URLs.
- you should delete VBSEO rewrite rules from .htaccess and put these Rules there

RewriteEngine on
RewriteRule [^/]+/([\d]+)-.+-([\d]+).html showthread.php?t=$1&page=$2 [NC,L]
RewriteRule [^/]+/([\d]+)-.+.html showthread.php?t=$1 [NC,L]