trying to work with WinSCard

[Ray]

I am having a problem with issuing commands to my smartcard, I converted the
call to SCardTransmit as follows:

[C#]

[DllImport("WinS Card.dll", EntryPoint="SCa rdTransmit",
CharSet=CharSet .Unicode, CallingConventi on=CallingConve ntion.StdCall)]
public static extern uint SCardTransmit(
[In] uint hCard,
[In] byte[] pioSendPci,
[In] byte[] pbSendBuffer,
[In] int cbSendLength,
ref byte[] pioRecvPci,
[Out] byte[] pbRecvBuffer,
ref int pcbRecvLength);

and created byte arrays of the lengths needed to mimic each of the structs
that are supposed to be passed in/out, but when I call SCardTransmit, i get
an return value which means Invalid Parameter. I've tried several different
approaches, none of which worked any better. (first I actually had structs
created with all the layout sizes and offsets defined, but I decided to just
try this instead, but all give me the same response) If anyone has a clue
to what I am doing incorrectly here, please lemme know.

(BTW, I have called SCardEstablishC ontext, and SCardConnect before this call
successfully)

Thanks.

Ray