I am not sure I understand exactly what you mean, mainly because Nabble has a subscription that is independent of XWiki. So, first, if you want to post to XWiki, please make sure you are subscribed here:
http://lists.xwiki.org/mailman/listinfo/usershttp://lists.xwiki.org/mailman/listinfo/devsAre you subscribed to the list(s) above?