I am trying to send an extension message, which does not seem to be working

I have verified that my connection to the smartfox server does indeed work, and I have tested the extension from director using Lingo, doing _server.sendXtMessage("extname", "func", obj, "str") and this is successful. When I attempt to do the equivalent from within the .Net framework, like this:
smc.SendXtMessage("extension", "func", args, SmartFoxClient.XTMSG_TYPE_STR) where args is a Hashtable, and smc is of type SmartFoxClient, it appears that the message does not get sent. GetConnectionMode() is socket, and smc.IsConnected() is True. I am stuck, any help on this would be much appreciated, thanks.