IP Office 3.1 and 6416 Call Waiting

[tlobject]

I have a customer who needs the inbound caller id to scroll slower when the multiple calls come into a terminal. The number scrolls so quick that by they turn to look at the phone the number is gone. Does anyone know of a way to change this setting on the IPO or the phone itself? If their is not a way to change the speed is there a way to keep the last caller's number up?

Thanks,