How to call external dll files from AX

This is how u can call a dll from AX. I have used the Beep function in kernel32.dll
The parameters of Beep are 

BOOL Beep(DWORD dwFreq,DWORD dwDuration);

The AX Code is

static void AB_DLL(Args _args)
{
    DLL         winApiDLL           = new DLL('kernel32');
    DLLFunction Function            = new DLLFunction(winApiDLL,'Beep');
    Function.arg(extTypes::DWord,extTypes::DWord);
    Function.call(400,1000);

}

Run this and u'll hear a beep (if ur sound is on).