How can I set up the voicemail indicator on the base and on the phone to let me know I have a voicemail? I have the radio shack cordless phone 5.8 Ghz model 43-324. I have voicemail with my phone company. When I have a voicemail, when I lift up the handset, I hear a message telling me I have a voicemail but the phone voicemail indicator on the base and on the handset don't lit up. Can you help? the manual doesn't give much details