enable support for passing the ICEAUTHORITY shell variable to define where to create the ice auth file
diff -r -u xfce4-session-4.4.3.orig/xfce4-session/main.c xfce4-session-4.4.3/xfce4-session/main.c
--- xfce4-session-4.4.3.orig/xfce4-session/main.c	2009-02-23 15:29:11 -0600
+++ xfce4-session-4.4.3/xfce4-session/main.c	2009-02-23 15:41:53 -0600
@@ -68,6 +68,7 @@
   const gchar *lang;
   const gchar *sm;
   gchar       *authfile;
+  int          staticauthfile = TRUE;
   int          fd;
 
   /* check that no other session manager is running */  
@@ -94,16 +95,24 @@
     }
 
   /* check access to $HOME/.ICEauthority */
-  authfile = xfce_get_homefile (".ICEauthority", NULL);
+  authfile = g_getenv ("ICEAUTHORITY");
+
+  if (authfile == NULL){
+  	authfile = xfce_get_homefile (".ICEauthority", NULL);
+  	staticauthfile = FALSE;
+  }
+
   fd = open (authfile, O_RDWR | O_CREAT, 0600);
   if (fd < 0)
     {
       fprintf (stderr, "xfce4-session: Unable to access file %s: %s\n",
                authfile, g_strerror (errno));
+      if (staticauthfile == FALSE && authfile != NULL) g_free (authfile);
       exit (EXIT_FAILURE);
     }
-  g_free (authfile);
+
   close (fd);
+  if (staticauthfile == FALSE && authfile != NULL) g_free (authfile);
 }