Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 156755)
+++ channels/chan_sip.c	(working copy)
@@ -16720,8 +16720,12 @@
 	sipmethod = find_sip_method(msg);
 
 	owner = p->owner;
-	if (owner) 
+	if (owner) {
+		char textcause[10];
 		owner->hangupcause = hangup_sip2cause(resp);
+		snprintf(textcause, sizeof(textcause), "SIP %s", req->rlPart2);
+		pbx_builtin_setvar_helper(owner, "^^HANGUPCAUSETEXT", textcause);
+	}
 
 	/* Acknowledge whatever it is destined for */
 	if ((resp >= 100) && (resp <= 199))
Index: apps/app_dial.c
===================================================================
--- apps/app_dial.c	(revision 156755)
+++ apps/app_dial.c	(working copy)
@@ -875,6 +875,7 @@
 			f = ast_read(winner);
 			if (!f) {
 				in->hangupcause = c->hangupcause;
+				ast_channel_rinherit_variables(in, c);
 #ifdef HAVE_EPOLL
 				ast_poll_channel_del(in, c);
 #endif
@@ -915,6 +916,7 @@
 				case AST_CONTROL_BUSY:
 					ast_verb(3, "%s is busy\n", c->name);
 					in->hangupcause = c->hangupcause;
+					ast_channel_rinherit_variables(in, c);
 					ast_hangup(c);
 					c = o->chan = NULL;
 					ast_clear_flag64(o, DIAL_STILLGOING);
@@ -923,6 +925,7 @@
 				case AST_CONTROL_CONGESTION:
 					ast_verb(3, "%s is circuit-busy\n", c->name);
 					in->hangupcause = c->hangupcause;
+					ast_channel_rinherit_variables(in, c);
 					ast_hangup(c);
 					c = o->chan = NULL;
 					ast_clear_flag64(o, DIAL_STILLGOING);
@@ -2232,8 +2235,10 @@
 				ast_parseable_goto(peer, opt_args[OPT_ARG_CALLEE_GO_ON]);
 				ast_pbx_start(peer);
 			} else {
-				if (!ast_check_hangup(chan))
+				if (!ast_check_hangup(chan)) {
 					chan->hangupcause = peer->hangupcause;
+					ast_channel_rinherit_variables(chan, peer);
+				}
 				ast_hangup(peer);
 			}
 		}
Index: include/asterisk/channel.h
===================================================================
--- include/asterisk/channel.h	(revision 156755)
+++ include/asterisk/channel.h	(working copy)
@@ -1462,6 +1462,7 @@
   channel with their names unchanged.
 */
 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
+void ast_channel_rinherit_variables(struct ast_channel *parent, const struct ast_channel *child);
 
 /*!
   \brief adds a list of channel variables to a channel
Index: main/channel.c
===================================================================
--- main/channel.c	(revision 156755)
+++ main/channel.c	(working copy)
@@ -3736,21 +3736,21 @@
 	ast_string_field_set(chan, name, newname);
 }
 
-void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child)
+static void channel_inherit_variables(const struct ast_channel *source, struct ast_channel *destination, const char c)
 {
 	struct ast_var_t *current, *newvar;
 	const char *varname;
 
-	AST_LIST_TRAVERSE(&parent->varshead, current, entries) {
+	AST_LIST_TRAVERSE(&source->varshead, current, entries) {
 		int vartype = 0;
 
 		varname = ast_var_full_name(current);
 		if (!varname)
 			continue;
 
-		if (varname[0] == '_') {
+		if (varname[0] == c) {
 			vartype = 1;
-			if (varname[1] == '_')
+			if (varname[1] == c)
 				vartype = 2;
 		}
 
@@ -3758,14 +3758,14 @@
 		case 1:
 			newvar = ast_var_assign(&varname[1], ast_var_value(current));
 			if (newvar) {
-				AST_LIST_INSERT_TAIL(&child->varshead, newvar, entries);
+				AST_LIST_INSERT_TAIL(&destination->varshead, newvar, entries);
 				ast_debug(1, "Copying soft-transferable variable %s.\n", ast_var_name(newvar));
 			}
 			break;
 		case 2:
 			newvar = ast_var_assign(varname, ast_var_value(current));
 			if (newvar) {
-				AST_LIST_INSERT_TAIL(&child->varshead, newvar, entries);
+				AST_LIST_INSERT_TAIL(&destination->varshead, newvar, entries);
 				ast_debug(1, "Copying hard-transferable variable %s.\n", ast_var_name(newvar));
 			}
 			break;
@@ -3776,6 +3776,16 @@
 	}
 }
 
+void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child)
+{
+	channel_inherit_variables(parent, child, '_');
+}
+
+void ast_channel_rinherit_variables(struct ast_channel *parent, const struct ast_channel *child)
+{
+	channel_inherit_variables(child, parent, '^');
+}
+
 /*!
   \brief Clone channel variables from 'clone' channel into 'original' channel
 
Index: main/chanvars.c
===================================================================
--- main/chanvars.c	(revision 156755)
+++ main/chanvars.c	(working copy)
@@ -71,8 +71,14 @@
 	/* Return the name without the initial underscores */
 	if (name[0] == '_') {
 		name++;
-		if (name[0] == '_')
+		if (name[0] == '_') {
 			name++;
+		}
+	} else if (name[0] == '^') {
+		name++;
+		if (name[0] == '^') {
+			name++;
+		}
 	}
 	return name;
 }