Dear saivenkat ,
When you call a gateway service endpoint using soap UI, or any client, the soap UI build a request and sends to gateway, gateway route this request to the backend server.
When you run it as schedule task, there is no client to send the request, the default request variable is empty -- that means you will need to build the request in your policy before routing to backend server.
But, I don't see a reason why you download file by a schedule task? Even you retrieve the file successfully, you have no requestor(client) to return the response.
Regards,
Mark