LsaAddAccountRights: How to marshal SID_IDENTIFIER_AUTHORITY

Hi Experts,

does anybody know how to use LsaAddAccountRights in C# ?

This is my declaration:

[System.Runtime.InteropServices.DllImport("advapi32.dll")]
private static extern long LsaAddAccountRights(
  IntPtr PolicyHandle,
  IntPtr AccountSid,
  LSA_UNICODE_STRING UserRights,
  long CountOfRights );

The function requires a SID buffer, so I also have to declare AllocateAndInitializeSid and LookupAccountName...

private static extern bool AllocateAndInitializeSid(
 SID_IDENTIFIER_AUTHORITY pIdentifierAuthority,
 int nSubAuthorityCount,
 long dwSubAuthority0, long dwSubAuthority1,
 long dwSubAuthority2, long dwSubAuthority3,
 long dwSubAuthority4, long dwSubAuthority5,
 long dwSubAuthority6, long dwSubAuthority7,
 out IntPtr pSid );

[System.Runtime.InteropServices.DllImport("advapi32.dll")]
private static extern bool LookupAccountName(
 String lpSystemName,
 String lpAccountName,
 IntPtr Sid,
 ref int cbSid,
 String DomainName,
 ref int cbDomainNameSize,
 IntPtr peUse);

...and SID_IDENTIFIER_AUTHORITY:

[StructLayoutAttribute(LayoutKind.Auto)]
class SID_IDENTIFIER_AUTHORITY {
 [MarshalAsAttribute(UnmanagedType.LPArray)]
 public byte[] Value;
}


At runtime AllocateAndInitializeSid throws an exception:
"System.Runtime.InteropServices.MarshalDirectiveException: parameter #1 cannot be marshalled:
The type Definition contains no layout informationen."

So I have changed the StructLayot-Attribute:

[StructLayoutAttribute(LayoutKind.Sequential)]
class SID_IDENTIFIER_AUTHORITY {
 [MarshalAsAttribute(UnmanagedType.LPArray)]
 public byte[] Value;
}

With that declaration AllocateAndInitializeSid throws a different exception:
"System.TypeLoadException: Field Value in type in type SID_IDENTIFIER_AUTHORITY cannot be marshalled:
This type cannot be marshalled as a structure field."


What's wrong with my declaration?
I can't find a readable example, so every hint would be very great!

greets,
coco