Swipe the File Libararies link "feature" from the stock web.

web/root/ecWeb/sidebar/004-fileLibraries.ssjs

+var ftp_url="ftp://";
+if(user.number && !(user.security.restrictions&UFLAG_G))
+	ftp_url += user.alias + ":" + user.security.password + "@";
+var host = http_request.host;
+if(!host || !host.length)
+	host = system.host_name;
+var port = host.indexOf(':');
+if(port>=0)
+	host=host.slice(0,port);
+ftp_url += host;
+ftp_port=webIni.ftpPort;
+var ftp_port;
+if(ftp_port==undefined)
+	ftp_port=21;
+if(ftp_port!=21)
+	ftp_url += ftp_port;
+ftp_url +="/00index.html?$" + new Date().valueOf().toString(36);
+print('<a class="link" href="'+encodeURI(ftp_url)+'">File Libraries</a>');