From your Gold SIM Travel number dial:  *146*711#
Message on the screen shows: 
"Viber calls are enabled. Incoming calls from Viber are charged"
From Viber call the registered Gold SIM Travel number as:
003728005xxxxxxx.
Calls to Gold SIM Travel number received from Viber are charged
o.15/min in all countries where incoming calls are free.
FREE from Viber
Call Gold SIM Travel number
from Viber and
IT COSTS YOU NOTHING !!!
Example: 
If you want to call Gold SIM Travel number
37254445678,   
you will dial from Viber 00
37280054445678
Activation
Making Calls
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