I believe that there is a bundled Kepware Enterprise with the Panelview+ 1000.
Look if Beckhoff ADS is in the list of drivers.
Possible alternatives I can think of:
Beckhoff has an OPC server for Win CE. You can investigate if it is possible to install a 3rd party OPC server on the PV+ panel.
Add a Modbus RTU to the Twincat PLC. I am pretty certain that PV+ supports Modbus RTU. I can imagine that the exchange of data will not be so smooth, as you dont have direct access to all controller tags, but to fixed Modbus registers.
Examine if the PV+ can access an OPC server remotely.
You could install a Beckhoff OPC server on the PC, and let the PV+ access this remote OPC Server. Not sure if it is even possibe, and if it is it is probably tricky to pull off.
Exchange the PV+ for an IPC with RSView ME RT. Connect to the TwinCat PLC via an OPC Server on the IPC.