As per XEP-0071 (http://xmpp.org/extensions/xep-0071.html#wrapper) the namespace for the XHTMLExtension class should be amended as follows:
public static const NS:String = “http://www.w3.org/1999/xhtml”;
public static const NS:String = “http://jabber.org/protocol/xhtml-im”;
Note that the spec also requires the element of the XHTML message payload to be formed as follows:
Failure to use the correct namespace seems to cause the parsing of the inbound raw xml to truncate the element with no warning.
No patch included here pending outcome of this thread: http://www.igniterealtime.org/community/thread/40815?tstart=0