First of all, great work with the Jabber plugin!
There are issues with certain Jabber servers that must require the SSLSocketFactory to connect to.
This feature is available in Pidgin as "Force old (port 5223) SSL".
It would be great to offer something similar in the Jabber plugin
I succeeded in this with a simple program using the Smack 3.1.0 API and just setting the SocketFactory to SSLSocketFactory.getDefault() as you see below:
ConnectionConfiguration config = new ConnectionConfiguration("<hostname>", 5223, "<servicename>");
XMPPConnection connection = new XMPPConnection(config);