caldera,
The documentation says one thing and it's implemented another way. After many tries i was able to get it working.
Here are the correct calls:
START SCAN:
"{\"module\": \"Recon\", \"action\": \"startScan\", \"scanType\": \"2\", \"scanDuration\": \"" + duration + "\", \"apiToken\": \"" + token + "\"}"
GET RESULT - call it until you get the results after the specified duration:
{\"module\": \"Recon\", \"action\": \"scanStatus\", \"scanID\": " + scanID + ", \"percent\": 0, \"apiToken\": \"" + token + "\"}