Asep,
The first problem is that you are using the FXO ports on the quintum which do not support connection direct to a phone and do not work that way. If you are trying to connect phones from one office to another, you will really need to use the FXS ports (if your quintum has these port active).
I would need to discuss this directly as there are many ways to do what you want, all depends on the specifics.
Please contact me at mike_voip@hotmail.com.
Mike