Using XMPP/Openfire and public-IM-networks (with all services of the Openfire-Server) with one IM-Client?

we wanted to use for our company the openfire server. However, it should be possible to use (with the company’s notebook - from home) networks (ICQ, MSN …). It should be only one IM-Client on the notebook. With miranda or pidgin is that possible. Unfortunately, the access to the services of the openfire-servers with miranda or pidgin is very limited. Spark can’t be used with public networks (only via transports internally). What opportunities are there?

It would be the best solution, if I simply log in Spark may indicate a public network.

Have you already tried the gateway plugin in openfire?