this is driven by user needs -- and may need know some internal of the package. please refer
http://www.litespeedtech.com/support/wiki/doku.php?id=litespeed_wiki:litespeed:cache:vbulletin
1. Save the following Cache plugin for vBulletin 3/4 to a file say litespeed_cache.xml
this is special knowledge in vBulletin.
without it, it's not possible to enable litespeed cache for vBulletin.
if you know XenForo has similar feature or configuration, we can cooperate to try to enable litespeed cache for it.