| [in] usn | The user-name that you need to use to authenticate on this interface. |
| [in] pwd | The password that you need to use to authenticate on this interface. |
| [in] options | String parameter. This is currently unused and reserved for future versions of the API. Pass in an empty string. |
| [in] vehicleID | The Blue Tree vehicle identifier for the truck. |
| [in] timestamp | The date time from which the trailer should be associated with the truck |
| [in] trailerNo | String parameter. The registration of the trailer. |
| [out] errorMsg | If an error happpens this string contains the error message. In case an error has happened (this variable contains a valid non-empty string) then the return value will not contain any usable data, do not try to parse it as an xml. |
Please see this page.