In the meantime - i am using dbus mesages to save the recording files in the format of [Rec-[Date]-[start time]-[end time].aac].
i am calling my scripts at call establishment and call end - 2 events:

[script] * * com.nokia.mce.signal sig_call_state_ind active normal
[script] * * com.nokia.mce.signal sig_call_state_ind none normal

works perfectly