Delegate doesn't seem to register 'params'

The params keyword of C# allows equivalence between Array and parameter-list, does it not?

Sadly, in my implementation, this isn't the case.

private Entities queryType(String entitiesType, params KeyValuePair<String, object>[] values)
{
    addStandardHeaders();
    String query = parsePredicate(values);
    Task<HttpResponseMessage> filterTask = client.GetAsync(client.BaseAddress + RESTapi.ALMentitiesQuery(domain, project, entitiesType, query));
    Task.WaitAny(filterTask);
    //Callback:
    HttpResponseMessage result = filterTask.Result;
    if (result.IsSuccessStatusCode)
    {
        updateCookies(client.BaseAddress+RESTapi.ALMentitiesQuery(domain, project, entitiesType, query));
        mainHeaders.Clear();
        Task<Stream> output = result.Content.ReadAsStreamAsync();
        Task.WaitAny(output);
        //Callback:
        return (Entities)fromJSON(output.Result, typeof(Entities)); 
    }
    else
    {
        util.Exception exception = getException(result);
        throw new HttpException(exception.Title);
    }
}

The delegate:

public delegate Entities SubTypeQuery(String subType, params KeyValuePair<String, object>[] values);

In application:

public List<Run> getRuns()
{
    List<Entity> selection = ((Entities)subTypeSelector.DynamicInvoke(
        ALMObject.Run.entitiesName(),
        (new KeyValuePair<String, object>("testcycle-id", id))
    )).entities.ToList<Entity>();

    List<Run> runSet = new List<Run>();
    foreach (Entity element in selection)
        runSet.Add(new Run(element, subTypeSelector));
    return runSet;
}

At run-time I get a Type-Exception: "Cannot convert KeyValuePair<String, object> to KeyValuePair<String, object>[]". This renders params completely useless. Suggestions?