[mythtv-users] test decrytability

[mythtv-free]

Hello all,
I am installing a DVB-S2 tuner in order to replace sur official box 
provided by our sat company. I can read the card with the keys, and scan 
the channels with the physical tuner.
I cant scan with the virtual scanner created by sasc.
So I dont understand the option "test decriptability" on the scan window 
of mythtv-setup.
do you known when I can use it ?