[timeout_or_invalid]
exten => t,1,Goto(s,1)
exten => i,1,Goto(s,1)

[menu1_1]
exten => s,1,Background(bb07)
exten => s,2,Background(bb08)
exten => 9,1,Goto(menu1,s,2)
include => timeout_or_invalid

[menu1]
exten => s,1,Background(bb06)
exten => s,2,Background(bb09)
exten => s,3,Background(bb08)
exten => 1,1,Goto(menu1_1,s,1)
exten => 2,1,Goto(menu1_2,s,1)
exten => 9,1,Goto(mainmenu,s,2)
include => timeout_or_invalid


output from asterisk 1.4.1:
= CDR updated on SIP/102-081cf730
    -- Executing [1@mainmenu:1] Goto("SIP/102-081cf730", "menu1|s|1") in new stack
    -- Goto (menu1,s,1)
    -- Executing [s@menu1:1] BackGround("SIP/102-081cf730", "bb06") in new stack
    -- <SIP/102-081cf730> Playing 'bb06' (language 'en')
    -- Executing [s@menu1:2] BackGround("SIP/102-081cf730", "bb09") in new stack
    -- <SIP/102-081cf730> Playing 'bb09' (language 'en')
  == CDR updated on SIP/102-081cf730
    -- Executing [1@menu1:1] Goto("SIP/102-081cf730", "menu1_1|s|1") in new stack
    -- Goto (menu1_1,s,1)
    -- Executing [s@menu1_1:1] BackGround("SIP/102-081cf730", "bb07") in new stack
    -- <SIP/102-081cf730> Playing 'bb07' (language 'en')
  == CDR updated on SIP/102-081cf730
    -- Executing [9@menu1_1:1] Goto("SIP/102-081cf730", "menu1|s|2") in new stack
    -- Goto (menu1,s,2)
    -- Executing [s@menu1:2] BackGround("SIP/102-081cf730", "bb09") in new stack
    -- <SIP/102-081cf730> Playing 'bb09' (language 'en')
    -- Executing [s@menu1:3] BackGround("SIP/102-081cf730", "bb08") in new stack
    -- <SIP/102-081cf730> Playing 'bb08' (language 'en')
  == Auto fallthrough, channel 'SIP/102-081cf730' status is 'UNKNOWN'