You can use almost all wiki plugins in any textarea of any of the Tiki Features, except in some rare cases.
As you found out, Convene is one of those rare cases. The way it was implemented requires from a wiki page to keep a history of changes in the convention call.
And report back with your progress... so that we know for other users asking a similar question...
I did run out of money to pay for extensions in the PluginConvene, and feel free to get a consultant to extend Convene for other cases, or to remove the dependency on wiki pages, etc.
I hope this helps,
P.S: And welcome to the Tiki Community! (only 4 posts, as I see)