It does appear that the controller mentioned utilizes CANOpen only. I would not say that this makes it impossible to talk to with the Due. However, it would require someone to code up support for CANOpen on top of the existing canbus library. That someone has not yet materialized. I have been thinking about adding support for some higher level protocols but the thing is, well, I just don't have any need for them myself. Pretty much everything I'd interface with uses vanilla canbus. So, the options are, take the library and add on support for CANOpen, find some existing code to do that (though I don't know of anything that really fits the bill), or somehow motivate someone other than you to do it. The joy of open source is that you've got a head start. The downside is that people only work on stuff they want/need.