发送Ctrl + C到以exec开始的进程

I'm trying to send a CTRL-C event to a java process started with exec.

cmd := exec.Command("javaw", "-cp", "burst.jar;conf", "brs.Burst") 
cmd.Dir = burstCmdPath
cmd.Env = append(os.Environ())
err = cmd.Start()
...
cmd.Process.Signal(syscall.SIGINT)

Unfortunately, the SIGINT-signal does not work on windows. I do not want to KILL the process. I just want to close it gracefully with CTRL-C.

I tried several things:

1. Calling taskkill: Process does only react to forced kill.

2. Using win32-API:

   ...
   d, err := syscall.LoadDLL("kernel32.dll")               
   p, e := d.FindProc("GenerateConsoleCtrlEvent")
   r, _, e := p.Call(syscall.CTRL_C_EVENT, uintptr(cmd.Process.Pid))
   if r == 0 {
       fmt.Print("GenerateConsoleCtrlEvent: %v
   ", e)
   }
   ...
   

   Does not throw any errors, but does not work either.

If you open burst.jar inside a shell, you can just press CTRL+C to signal a shutdown, but why not with exec? Any ideas?