Step 1: Go to Settings --> Mobile devices --> New mobile device with own data : Add
Step 2: Add SIP credentials and change Displayname to TBR22_EN300494. The value "TBR22_EN300494"for the Diplayname is necessary to change the random PIN to "0000"
Step 3: Start the registration with Button " Start Registration"
Pin for mobile device registration is set to "0000"