I have a customer with an IP Office 500 in Partner mode and embedded voicemail. They are still using their Partner 18D phones. I have programmed a Voicemail Collect button on the phones and I have also tried just feature 00 and intercom 777. Both options work, but only when on speaker, not when you lift the handset. If you lift the handset and touch the voicemail button, it just gives back dial tone, but if you hit speaker and the voicemail button, it works just fine. This is happening on all their phones. Any thoughts?