Hi all ;)

I am looking for a WikiEngine, preferably a PHP/MySql-based one, that
has the ability to comment on WikiPages. I know, that sound odd. Let me
explain.

The Wiki will be an online version of a printed handbook. Users should
be able to 'comment' to pages, e. g. ask questions, discuss issues, ...
These comments must not be part of the WikiPage. The handbook's content
must not be altered when commenting.

I know of one WikiEngine that does this, WakkaWiki [1]. Is this really
the only WikiEngine with this ablility?

cu, Sascha

PS: PHP/MySql would be great, but I will not turn down a Perl solution
if there is any.

[1] http://www.wakkawiki.com/