title: Fluent Nhibernate 1.0 - Specify foreign key constraint name between class and joined subclass
body: <p>I think this should be simple, but I can't figure out how to do it.  Suppose I have the following maps:</p>
  
  <pre><code>public class AnimalMap : ClassMap&lt;Animal&gt; { Id( x =&gt; x.Id); }
  
  public class CatMap: SubclassMap&lt;Cat&gt; {
      Extends&lt;AnimalMap&gt;();
      Map(x =&gt; x.IsDomestic);
  }
  </code></pre>
  
  <p>Which creates tables as I expect:</p>
  
  <pre><code>Animal
  ------
  Id
  
  Cat
  ----
  AnimalId : FK to Animal (named FK3500ABA0D)
  IsDomestic
  </code></pre>
  
  <p>As noted, the FK gets generated by the db and ends up as FK3500ABA0D.  All I want to do is set the name of that constraint, but I can't find how to do it via Fluent NHibernate (or actually even plain NHibernate, for that matter).</p>
  
  <p>So, what am I missing?</p>