C# Generics boxing errors
<p>I have the following code that worked before I changed to use generics for the service:</p>

<p><strong>Update:</strong> I added some more class and interface info in response to comments:</p>

<pre><code>public class Service&lt;T1,T2&gt; : BaseService, IService&lt;T1&gt;
        where T1 : IAuditableTable
        where T2 : IAuditableTable
{
    private IAzureTable&lt;T1&gt; _T1repository;
    private IAzureTable&lt;T2&gt; _T2repository;

    public Service(string ds)
    {
        base.Initialize(ds);
        _T1repository = StorageHelper.GetTable&lt;T1&gt;(ds);
        _T2repository = StorageHelper.GetTable&lt;T2&gt;(ds);
    }

    public IEnumerable&lt;AdminDetail&gt; ShowDetails()
    {
        return base.ShowDetails(_T1repository, _T2repository);
    } 

    ...
</code></pre>

<p>and</p>

<pre><code>public IEnumerable&lt;AdminSummary&gt; ShowSummary&lt;T1, T2&gt;(
        IAzureTable&lt;T1&gt; master, IAzureTable&lt;T2&gt; detail)
    where T1 : AuditableTable
    where T2 : AuditableTable
{
    ...

public abstract class AuditableTable : TableServiceEntity, IAuditableTable  
{
    ...

public interface IAzureTable&lt;T&gt; : IInitializer

public interface IService&lt;T&gt;
        where T : IAuditableTable
    {
        IEnumerable&lt;AdminSummary&gt; ShowSummary();
    }

private IService&lt;Account&gt; _account;
vm.AdminSummaries = _account.ShowSummary(); &lt;&lt; calls the report
</code></pre>

<p>When I try to compile I get the following message:</p>

<blockquote>
  <p>The type 'T2' cannot be used as type parameter 'T2' in the generic type or 
  method 'Services.BaseService.ShowSummary&lt;T1,T2>(AzureToolkit.IAzureTable&lt;T1>, AzureToolkit.IAzureTable&lt;T2>)'. There is no boxing conversion or type parameter conversion from 'T2' to 'Storage.Models.AuditableTable'.</p>
</blockquote>
