This is not vbSEO compatible immediately. The mod SEOs its URLs in a similar fashion to MediaWiki.
The URLs can look like either of the following:
http://www.vaultwiki.org/showwiki.ph...Demo:Main+Page
http://www.vaultwiki.org/wiki/Demo:Main+Page
vbSEO doesn't know how to handle this, so an .htaccess patch is required.