Just tried this with YAM 2.7-dev, WookieChat 2.12b2 and codesets.lib 6.12 without any problem on my WinUAE/OS3 setup. Hence, in general it shold work.

Perhaps you can try to contact James Carroll yourself to give hime some more details: james.carroll.jahc@gmail.com

I contacted him already and pointed him to this thread, but so far I got no answer yet. Maybe its the wrong time for NZ.