Has anybody ever done a diret transfer to a mailbox. Can't get it to work
Don't use the transfer key; use the voice mail key.
VM, mailbox number, hang up.
Does that work on a 5530 phone, that has the white enevolpe button
That is not the voicemail key. That is the message key. It is for responding to messages, not transferring calls to voicemail.
Program a key as a DSS key with the ext number of the Voice Mail (you will find it under voice mail/devices/applications on the right you will see the Voice Mail application number) put that on a key of the phone and it will be your transfer to voice mail key.
Randy