I highly recommend using the BACnet Configurator software along with the Codesys Add-on Solution Builder, both of which are available on the WAGO Download Center.
Here is a short guide that may help you get going: How To: Add BACnet to a WAGO CODESYS project
I consider this a much easier method than directly utilizing WagoSysBacnet, and gives access to a wider range of BACnet object types, including IntegerValue.