Ringing indicator

Hi all

i have been looking how to solve this for more than month and seems no one got any answer.

everything work smooth and gr8 but i face one problem

when i dial from SIP to SIP in same BOX i cant hear ringing tone while its ringing i just hear silence until the other sip extention pickup.

-- AGI Script Executing Application: (Dial) Options: (SIP/2856|60|rHL(154600000:61000:30000))
-- Limit Data for this call:
-- - timelimit     = 154600000
-- - play_warning  = 61000
-- - play_to_caller= yes
-- - play_to_callee= no
-- - warning_freq  = 30000
-- - start_sound   = UNDEF
-- - warning_sound = timeleft
-- - end_sound     = UNDEF
-- Called 2856
-- SIP/2856-0969 is ringing

i just face this issue just when i dial between SIP to SIP on the same box
if the sip dial an VOIP provider truk things goes smooth and i can hear the ringing tone

anyone knows how to solve this issue? i’m using ATA HT on G729 but i dont have G729 installed i guess they call this G729 pass thru.