sorting - C# : Sort list on custom property

I am sorry if this is duplicate. Please point to correct question.

I have a class called MyDate like below

public class MyDate
{
    private SqlDateTime m_dateTime;


    public MyDate(DateTime dateTime)
    {
       if (DateTime.Compare(dateTime, (DateTime)SqlDateTime.MinValue) <= 0)
            m_dateTime = SqlDateTime.MinValue;
        else
            m_dateTime = dateTime;
    }

    public string MMDDYYYYHHMMSS

    {
       get
         {
            if(m_dateTime > SqlDateTime.MinValue)
                return m_dateTime.Value.ToString("MM/dd/yyyy hh:mm:ss tt");
            else
                return String.Empty;
         }
    }
}

I have class called MyEvent like below

public class MyEvent
{
  public int EventId{get;set;}
  public MyDate StartDate{get;set;}
}

I have collection of MyEvent like

List myEvents. 

Now I need to sort myEvents in descending order of StartDate. The problem I have is I cannot add IComparable or change MyDate since it is written by other team and I just refer dll. I donot have control on MyDate code. Can anybody help me how I can do. I created a new comparer class that implements IComparer but unable to understand how to use it and sort myEvents.

**UPDATE 1 **

Thank you very much for Alexei, Ehsan and Dave for helping me out. I tried Dave's answer and it worked. I was trying to do it in more better way so that there is no need to add any new properties. I didnot try Ehsan way of using StringDateComparer but it helped me to understand how I can use Comparer in Order linq statements. At last as pointed by Alexei I did like below

**UPDATE 2 **

Sometimes I am getting empty string for e2.StartDate.MMDDYYYYHHMMSS and/or e2.StartDate.MMDDYYYYHHMMSS so I changed my code like below

myEvents.Sort(
                delegate(MyEvent e1, MyEvent e2)
                 {
                     DateTime dt1;

                     DateTime dt2;
                     DateTime.TryParse(e1.StartDateTime.MMDDYYYYHHMMSS, out dt1);
                     DateTime.TryParse(e2.StartDateTime.MMDDYYYYHHMMSS, out dt2);

                     return dt2.CompareTo(dt1); // descending
                     //return dt1.CompareTo(dt2); // ascending
                    }
            );