Hi
I think I am very close to solve this issue, based on suggestions of Tavis and Klaus for openser in:
http://openser.org/dokuwiki/doku.php?id=how_to_set_up_nathelper_rtpproxy_when_both_sip_ua_s_are_behind_same_nat

I´ve been able to disable rtpproxy in this cases but I have a problem with accounting, if the callee hungup first appears an error and no cdr for BYE is generated until caller hungup the call, bellow the errors and config.

thanks for any help
rafael

 4(22193) BYE  - STOP ACCOUNTING
 4(22193) DEBUG: add_param: tag=3658302912
 
 4(22193) grep_sock_info - checking if host==us: 13==13 &&  [192.168.1.205] == [ 10.0.2.130]
 4(22193) grep_sock_info - checking if port 5060 matches port 5060
 4(22193) grep_sock_info - checking if host==us: 13==9 &&  [192.168.1.205] == [ 127.0.0.1]
 4(22193) grep_sock_info - checking if port 5060 matches port 5060
 4(22193) check_self: host != me
 4(22193) grep_sock_info - checking if host==us: 13==13 &&  [10.0.2.130] == [ 10.0.2.130]
 4(22193) grep_sock_info - checking if port 5060 matches port 5060
 
 4(22193) check_via_address(10.0.1.25, 192.168.1.100, 0)
 4(22193) ERROR: udp_send: sendto(sock,0x4051e800,588,0
,0x4051f2ac,16): Operation not permitted(1)
 4(22193) msg_send: ERROR: udp_send failed
 4(22193) ERROR:tm:t_forward_nonack: sending request failed
 4(22193) DEBUG: add_to_tail_of_timer[4]: 0x4051f2cc
 4(22193) DEBUG: add_to_tail_of_timer[0]: 0x4051f2dc
 4(22193) ERROR:tm:t_relay_to:  t_forward_nonack returned error
 4(22193) parse_headers: flags=ffffffffffffffff
 4(22193) check_via_address(10.0.1.25, 192.168.1.100, 0)
 4(22193) WARNING:vqm_resize: resize(0) called
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