A few months ago I posted something on a very active wall of a public Facebook event. It's the only thing I posted there. I might be able to remember some keywords if necessary, but I can't find a way to direct a search to match all postings on an event's wall.
The solution doesn't have to be any one-button wonder. For example, I'm willing to even look into some weird Greasemonkey scripting solutions (to get full the contents of the wall downloaded as a web page, or something like that), if such exist.
How can I find my wall post?
https://graph.facebook.com/[EVENTID]/feed?access_token=[ID]
and then add theq=[query]
then hopefully it can work. It sounds like this would needread_stream
permissions (just a guess), so a minimal app is needed.