Set_config_parameter to negative value not working

I’m trying to calibrate a temperature sensor that is off, but it seams that I can’t send negative values?

Here is what I’m sending:

  "node_id": 2,
  "parameter": 66,
  "value": "-2"

And here is the log output:

16-12-14 23:16:40 homeassistant.core: Error doing job: Future exception was never retrieved
Traceback (most recent call last):
  File "/usr/lib/python3.4/concurrent/futures/", line 54, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/hass/hass_venv/lib/python3.4/site-packages/homeassistant/", line 1045, in execute_service
  File "/srv/hass/hass_venv/lib/python3.4/site-packages/homeassistant/components/zwave/", line 462, in set_config_parameter
    node.set_config_param(param, value, size)
  File "/srv/hass/hass_venv/lib/python3.4/site-packages/openzwave-0.3.1-py3.4.egg/openzwave/", line 953, in set_config_param
    return self._network.manager.setConfigParam(self.home_id, self.object_id, param, value, size)
  File "src-lib/libopenzwave/libopenzwave.pyx", line 3703, in libopenzwave.PyManager.setConfigParam (src-lib/libopenzwave/libopenzwave.cpp:27697)
OverflowError: can't convert negative value to uint32_t