Ciphermode

Hi guys.. I have a question about cipher mode. I saw, that currently a5/1 and a5/2 is implemented. Now, I want to force the phone to use no encryption (A5/0). Is it enough to disable both of these algos? Because when I tried that, I was not longer able to sign in.. Are there any patches that are necessary, or may it be, that the network is not willing to provide a non-encrypted connection? Usually, the phone is using A5/1 and with that algo, everything is working fine.. Thanks for your help. Ronny