CAN prototype for -1000 motor values

Hi, 
I am trying to understand the roboteq controller and tried running my motor via CANOpen. I run `CG` or CANGO. Using canutils `cansend` utility in Linux, I follow the frame structure specified in the `CANOpen` document  and send 

```console
2000200164000000      # 20 0020  01  64000000
```
I get the motor moving in a particular direction. Although the `CG` section mentions acceptable data range from -1000 to 1000. How do I try sending the -1000/negative values in order to change the direction of the motor ?

Can @_joas @Abilash95 @accrea @Adam Knight notify the mods ? There seems to be zero support from Roboteq.