C++ dll in VB.NET - Structure compatibility

Question

I'm using a C++ DLL in a VB.NET project.
I call some DLL function with success, but if I call a function that returns a C++ structure pointer I am getting this error:

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

Maybe I'm not creating the right structure in VB, could you help me?

This is how I declare and call the function in VB:

<System.Runtime.InteropServices.DllImport("MobilePosAdapterCLib.dll", CallingConvention:=CallingConvention.Cdecl, SetLastError:=False)> 
Public Shared Function MobilePosAdapter_getLastTransactionResult() As System.IntPtr 
End Function

Dim risultato As System.IntPtr
Dim risultato2 As PaymentResult
risultato = MobilePosAdapter_getLastTransactionResult()
risultato2 = Marshal.PtrToStructure(risultato, GetType(PaymentResult)) ' error here

This is the c++ struct:

typedef struct {
    char text[48 + 1];
    int attribute;
} ReceiptRow;

typedef struct {
    int numReceiptRows;
    int signatureRequired;
    ReceiptRow rows[200];
} Receipt;

typedef struct {
    int operationType;
    char posId[32 + 1];
    char terminalId[8 + 1];
    char transactionId[10 + 1];
    int transactionResult;
    char transactionDate[8 + 1];
    char transactionTime[9 + 1];
    char stan[6 + 1];
    int isReceiptPresent;
Receipt receipt;
} TransactionResult;

typedef struct {
    TransactionResult base;
    int amount;
    char pan[19 + 1];
    int cardType;
    int technologyType;
    char acquirerId[11 + 1];
    char acquirerName[16 + 1];
    char approvalCode[6 + 1];
    char merchantId[15 + 1];
    char actionCode[3 + 1];
    char posMessage[16 + 1];
    char emvApplicationId[32 + 1];
} PaymentResult;

And this is my VB.NET structure:

Public Structure ReceiptRow

    Public text As Char()
    ' tried also so:
    '<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=48)>
    'Public text As String

    Public attribute As Integer
End Structure

Public Structure Receipt
    Public numReceiptRows As Integer
    Public signatureRequired As Integer
    Public Shared rows() As ReceiptRow = Arrays.InitializeWithDefaultInstances(Of ReceiptRow)(200)
End Structure

Public Structure TransactionResult
    Public operationType As Integer
    Public posId As Char()
    Public terminalId As Char()
    Public transactionId As Char()
    Public transactionResult As Integer
    Public transactionDate As Char()
    Public transactionTime As Char()
    Public stan As Char()
    Public isReceiptPresent As Integer
    Public receipt As Receipt
End Structure

Public Structure PaymentResult
    Public base As TransactionResult
    Public amount As Integer
    Public pan As Char()
    Public cardType As Integer
    Public technologyType As Integer
    Public acquirerId As Char()
    Public acquirerName As Char()
    Public approvalCode As Char()
    Public merchantId As Char()
    Public actionCode As Char()
    Public posMessage As Char()
    Public emvApplicationId As Char()
End Structure

UPDATE:

Thanks to GSerg's comment I managed to get almost everything, my last problem is converting to VB.NET this part:

typedef struct {
    int numReceiptRows;
    int signatureRequired;
    ReceiptRow rows[200];
} Receipt;

It seems to work with:

Public Structure Receipt
    Public numReceiptRows As Integer
    Public signatureRequired As Integer
    <MarshalAs(UnmanagedType.ByValArray, SizeConst:=200)>
    Public rows As ReceiptRow()
End Structure