There's a WRG614. The port forwarding site's got a few versions listed but not a version 4, there's a v5 & v6. I'm guessing you'd just have to use the plain ol' 614 instructions so here they are
http://www.portforward.com/english/r...4/Limewire.htm

Don't forget to set up a static IP address first, there's a link (in red) for this within that set of instructions.
After you do that & set up port forwarding, go to LW's tools > options > advanced > firewall config. Choose the 'manual port forward' option & enter the same port number as LW's listening port > apply.