Off-Hook and ring back tone for transfer

Hello;
vicibox 4.0.3, vicidial 2.8-404a, Build 130605-0841, asterisk 1.4.39.1-vici, Single Machine, Vtiger 5.4
I am not able to hear the ring back tone using Transfer - Conf in both cases: Dial With Customer or Park Customer Dial, but using ON-HOOK I am able to hear ring back tone using Dial With Customer only and can not using Park Customer Dial. Doing a normal transfer from the IP Phone is going fine with the ring back tone.
Any method to resolve this?
Regards
Bilal
vicibox 4.0.3, vicidial 2.8-404a, Build 130605-0841, asterisk 1.4.39.1-vici, Single Machine, Vtiger 5.4
I am not able to hear the ring back tone using Transfer - Conf in both cases: Dial With Customer or Park Customer Dial, but using ON-HOOK I am able to hear ring back tone using Dial With Customer only and can not using Park Customer Dial. Doing a normal transfer from the IP Phone is going fine with the ring back tone.
Any method to resolve this?
Regards
Bilal