Implement some form of message length limitation in the xmppface
Most XMPP servers set a limit on message lengths (usually less than 64KiB; sometimes around 16).
One possible way to work around this in xmppface is to split messages' text into multiple messages; possibly — send further parts on special command request (e.g. ‘more’ or ‘ ’).
One of the largest problems with that way is providing equally split plaintext and XHTML message parts (or splitting XHTML at all).