I'm positive I've read and tried almost every recommendation on Message Wait Indicator to get it to work on my 7965 handsets with UC560.
I can leave a voicemail at the extension 210. I can dial 399 and listen to my voicemails from extension 210. I can see the A800 in the ccsip debug being sent to 210. I'll put this out there but surely I don't need to reboot the phone or uc560 after making the changes to resync MWI.
The entries in the service engine config match the ephone settings on the config.