SOAP Request works via SOAPUI, fails via C#

Question

I am trying to make a simple SOAP request to export some data. This works fine in SOAP UI as following:

However, when I try to replicate this via C# like this:

    srvEnablon.Security moo = new Security();
    moo.UsernameToken = new UsernameToken();
    moo.UsernameToken.Password = "blablabla";
    moo.UsernameToken.Username = "[email protected]";


    srvEnablon.EnablonWS_Serv srv = new EnablonWS_Serv();
    srv.SecurityValue = moo;
    srv.Url = "https://www.aurl.com";
    try
    {

      var res =  srv.ExportData(
        Table: "/ims/Incidents",
        FolderId: 0,
        FormatType: 3,
        Fields:"",
        CSVSeparator: 0,
        FormatOptions: 26,
        Filter: "id = 21662",
        ExportOptions: 0);

        int i = 1;
    }
    catch (Exception ex)
    {
        throw ex;
    }

I get an error as following : "Unable To Apply Export Filter: Invalid Date: Missing closing "#"." This seems to be related to the "Filter" tag and the html symbol for = (equals) used there. I try using the actual symbol itself instead of the html representation, but then the result is null, which means that no criteria matched.

Any ideas?

P.S. Using a filter is mandatory since the data is so much, I get a timeout if I don't.