Textile - how to onl allow certain tags?

#sanitize has VERBOTEN_TAGS and VERBOTEN_ATTRS switches:
http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#M000626

OTW, google whitelist:
http://www.kookdujour.com/blog/details/11
http://svn.techno-weenie.net/projects/plugins/white_list