dotnet variables / Array ObjectCollection

ottobe

I have created a .NET framework in C# that connects to a web service for downloading Invoices.
This works, except I cannot access the information in the invoices.

The Invoice object I get from the WS is an array/Object collection that contains a set of invoices, that in C# can be traversed using e.g. "foreach":

foreach (SalesInvoice i in s)
{
Console.WriteLine(i.OrderNumber.ToString());
}

s is the Invoice Array/Object Collection

But in C/AL i cannot access the SalesInvoices.
I can run the methods of the SalesInvoice object, but not get the properties.
I have tried to create the C/AL object as an array:

SI[1] := SI[1].SalesInvoice;
But
TextVar := SI[1].OrderNumber; fails with the error message:

"Method 'ClassLibrary....OrderNumber' not found". So the property is here interpreted as a Method.

So, how can such variables be declared, and how to get the properties?