Fluent NHibernate - HasOne mapped to a ReferencesAny -

i have following poco classes:

public class container {     public virtual int64 containerid { get; protected set; }     public virtual string name { get; set; }     public virtual location location { get; set; } }  public abstract class location {     public virtual int64 locationid { get; protected set; }     public virtual string name { get; set; } }  public class uniquelocation : location {     public virtual container container { get; set; } }  public class sharedlocation : location {     public sharedlocation()     {         this.containers = new list<container>();     }      public virtual ilist<container> containers { get; set; } } 

and following fluent mapping:

public class containermap: classmap<container> {     public containermap()     {         table("containers");         id(x => x.containerid);         map(x => x.name);         referencesany(x => x.location).identitytype<int64>().entitytypecolumn("locationtype").entityidentifiercolumn("locationid")             .addmetavalue<uniquelocation>("u")             .addmetavalue<sharedlocation>("s");     } }  public class locationmap : classmap<location> {     public locationmap()     {         table("locations");         id(x => x.locationid);         map(x => x.name);     } }  public class uniquelocationmap : subclassmap<uniquelocation> {     public uniquelocationmap()     {         hasone(x => x.container).propertyref(x => x.location).foreignkey("locationid").cascade.all().constrained();     } }  public class sharedlocationmap : subclassmap<sharedlocation> {     public sharedlocationmap()     {         hasmany(x => x.containers).keycolumn("locationid");     } } 

the problem hasone() mapping generates following exception: "broken column mapping for: container.location of: uniquelocation, type object expects 2 columns, 1 mapped".

how tell hasone() use/map both locationtype , locationid?

afaik conditions not possible on entity references except using formulas. design seems strange because nasty change unique location shared location.

what want can done using:

reference(x => x.container).formula("(select c.id container c c.locationid = id , c.locationtype = 'u')"); 

but prefere

class location {     ...     public virtual bool isunique { { return container.count == 1; } } }