SIP OK tooo early.

[MRFischer]

It´s me, again...

I´m connectin an OXO as the attached diagram.
These gateways are connected into to client remote site, and go into the trunk of an old analog PBX, where the bilingis done by reversing polarity.

In the main site there is also a call accounting system via V24 interface.
In the matrix, from where the calls get out, the local calls are billed perfectly. Only counts the time when the call is answered.
However, when the call is made behind the SIP gateway, the OXO sends the "OK" package (SIP) before the connection is effectively completed, and even if the connection is not completed.
"OK" This package should be sent only when a call is connected. However appears to be sent based on a timer.

What can I do about this?