Convert CookComputing XMLRpcStruct (IEnumerable<Object>) to an actual C# class

Question

So, I am using CookComputings XMLRPC library to be able to talk to InfusionSoft (it's an online CRM that's quite popular). The main method is:

 [XmlRpcMethod("DataService.query")]
 IEnumerable<object> QuerySubscriptionStatus(string apiKey, 
        string table, int limit, int page, 
        IDictionary queryData, string[] selectedFields);

I am REQUIRED to use an IEnumerable<object> sadly, as the InfusionSoft XML/RPC API requires it. I wish it wasn't the case, but sadly it is.

Since I use .NET 4.5, I figured I can just do a dynamic cast:

  var subStatus = proxy.QuerySubscriptionStatus(
      _key, "RecurringOrder", 500, 0, dict, sarray);
  var result = subStatus.Cast<SubscriptionStatus>();

Unfortunately, this doesn't work, I'm given a very upset error from C#:

Unable to cast object of type 'CookComputing.XmlRpc.XmlRpcStruct' to type 'WBI.Model.SubscriptionStatus'.`

I've tried specifying my class as a struct; heck I've even tried specifying it with XMLRpcMember() tags, but nope, it just wont convert.

How can I interact with the data in the IEnumerable?

Class/Struct Types I've Tried

public struct SubStatus
{
    public int AffiliateId;
    public int AutoCharge;
    public double BillingAmt;
    public string BillingCycle;
    public int CC1;
    public int CC2;
    public int ContactId;
    public DateTime EndDate;
    public int Frequency;
    public int Id;
    public DateTime LastBillDate;
    public int LeadAffiliateId;
    public int MaxRetry;
    public int MerchantAccountId;
    public DateTime NextBillDate;
    public int NumDaysBetweenRetry;
    public int OriginatingOrderId;
    public DateTime PaidThruDate;
    public int PaymentGatewayId;
    public int ProductId;
    public int ProgramId;
    public string PromoCode;
    public int Qty;
    public string ReasonStopped;
    public int ShippingOptionId;
    public DateTime StartDate;
    public string Status;
    public int SubscriptionPlanId;
}

I also just tried a simple class with the XMLRpcMember tags:

public class SubscriptionStatus
{
    [XmlRpcMember("AffiliateId")]
    public int AffiliateId { get; set; }
    [XmlRpcMember("AutoCharge")]
    public int AutoCharge { get; set; }
    [XmlRpcMember("BillingAmt")]
    public double BillingAmt { get; set; }
    [XmlRpcMember("BillingCycle")]
    public string BillingCycle { get; set; }
    [XmlRpcMember("CC1")]
    public int CC1 { get; set; }
    [XmlRpcMember("CC2")]
    public int CC2 { get; set; }
    [XmlRpcMember("ContactId")]
    public int ContactId { get; set; }
    [XmlRpcMember("EndDate")]
    public DateTime EndDate { get; set; }
    [XmlRpcMember("Frequency")]
    public int Frequency { get; set; }
    [XmlRpcMember("Id")]
    public int Id { get; set; }
    [XmlRpcMember("LastBillDate")]
    public DateTime LastBillDate { get; set; }
    [XmlRpcMember("LeadAffiliateId")]
    public int LeadAffiliateId { get; set; }
    [XmlRpcMember("MaxRetry")]
    public int MaxRetry { get; set; }
    [XmlRpcMember("MerchantAccountId")]
    public int MerchantAccountId { get; set; }
    [XmlRpcMember("NextBillDate")]
    public DateTime NextBillDate { get; set; }
    [XmlRpcMember("NumDaysBetweenRetry")]
    public int NumDaysBetweenRetry { get; set; }
    [XmlRpcMember("OriginatingOrderId")]
    public int OriginatingOrderId { get; set; }
    [XmlRpcMember("PaidThruDate")]
    public DateTime PaidThruDate { get; set; }
    [XmlRpcMember("PaymentGatewayId")]
    public int PaymentGatewayId { get; set; }
    [XmlRpcMember("ProductId")]
    public int ProductId { get; set; }
    [XmlRpcMember("ProgramId")]
    public int ProgramId { get; set; }
    [XmlRpcMember("PromoCode")]
    public string PromoCode { get; set; }
    [XmlRpcMember("Qty")]
    public int Qty { get; set; }
    [XmlRpcMember("ReasonStopped")]
    public string ReasonStopped { get; set; }
    [XmlRpcMember("ShippingOptionId")]
    public int ShippingOptionId { get; set; }
    [XmlRpcMember("StartDate")]
    public DateTime StartDate { get; set; }
    [XmlRpcMember("Status")]
    public string Status { get; set; }
    [XmlRpcMember("SubscriptionPlanId")]
    public int SubscriptionPlanId { get; set; }
}

Answer 1

So, after some extended help from another senior developer, it turns out we were able to make some changes to the struct:

    private string[] retFlds = { "Id", "ContactId", "OriginatingOrderId", "ProgramId", "SubscriptionPlanId", "ProductId", "StartDate", "NextBillDate", "BillingCycle", "Frequency", "BillingAmt", "Status", "ReasonStopped", "AutoCharge", "CC1", "CC2", "NumDaysBetweenRetry", "MaxRetry", "MerchantAccountId", "AffiliateId", "PromoCode", "LeadAffiliateId", "Qty", "ShippingOptionId" };
    private string table = "RecurringOrder";
    private DataTable dt = new DataTable();
    // here's the query 
    XmlRpcStruct[] retData = proxy.Query(Auth.key, table, 1000, 0, qryData, returnFields);
    dt = StructArrayToDT(retData);

    public static DataTable StructArrayToDT(XmlRpcStruct[] data)
    {
        DataTable dt = new DataTable();
        if (data.Length == 0) { return dt; }

        // do columns
        foreach (DictionaryEntry d in data[0])
        {
            dt.Columns.Add(d.Key.ToString(), typeof(object));
        }

        foreach (XmlRpcStruct xmlstruct in data)
        {
            DataRow dr = dt.NewRow();
            foreach (DictionaryEntry d in xmlstruct)
            {
                try
                {
                    dr[d.Key.ToString()] = d.Value;
                }
                catch (Exception ex)
                { 
                    // handle errors
                }

            }
            dt.Rows.Add(dr);
        }
        return dt;
    }

Finally can access that data without any issue now.