Sigfox callback error 400 when using SDR dongle



I have an error 400 when trying to configure the sigfox callback with Losant running on sigfox SDR dongle, for this i use post method and jason application, The origin of this problem is caused by “&” character appearing at the beginning of the json body when receiving data in losant workflow, losant can not read the command and it responses by error which viewed by red sign in sigfox callback interface.
This issue has been identified as a bug and sigfox is working on it to be fixed for the next SNE software release.
waiting for new version, is there any solution to bypass this problem ? how can I send data using Put / get method ??

Thank you in advance.