Welltech LanPhone 101 Behind Firewall

Hello

I have searched through and found some answers in this forum , BUT the setup still does not work.
Basically I have 1 phone behind the firewall and one outside , the phones are set in P2P a gatekeeper is not used.
My problem is finding which ports in what format to open .

I have tried all the ones shown here , the phone inside will dial out the outside phone can here the internal phone but the internal cannot here the external phone.When the external phone dials the internal phone i pick up the internal phone but the external is still dialling ( fails to connect )

Any help ?????

Simon