Hello John,
my mistake, I miss read this.
You should be able to use this and I am unsure why it would not work.
The next step is to contact your Polycom reseller so tehy can open a support case for you with Polycom support.
If you struggle identifying who that would be please provide the MAC address of the phone in question.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services