pinvoke CryptSetKeyParam not working?   

Hi,
  I'm trying to use AES encryption from the win32 cryptoAPIs using pinvoke.  
My C# code pinvoke signature reads like this:
        [DllImport("advapi32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool CryptSetKeyParam(IntPtr hKey, uint 
dwParam, byte[] pbData, uint dwFlags);
and then I setup CryptGetKeyParam

        [DllImport("advapi32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool CryptGetKeyParam(IntPtr hKey, uint 
dwParam, byte[] pbData, ref uint pdwDataLen, uint dwFlags);


Are these signatures right?  When I call CryptSetKeyParam to set the 
initialization vector and then immediately call CryptGetKeyParam, I get back 
all zeros for the initV instead of the value I supplied previously.

date: Fri, 18 Jul 2008 06:16:15 -0700   author:   David Moore am