Using NHibernate.Mapping.Attributes on assembly with dependancies

Question

Within my Entity assembly I have a class:

public class MyClass : IAuditObject
{
    // Implementation here
}

However the interface IAuditObject is defined in a separate Audit assembly.

How can I successfully generate mappings using:

NHibernate.Mapping.Attributes.HbmSerializer.Default.Serialize(MappingFile,EntityAssembly);

where EntityAssembly is dependant on Audit assembly for the IAuditObject interface?

Thanks.