Per instance id increments

gistfile1.cs

public interface IGenerateMyId
{
    string GenerateId();
}

//This is used within my IoC registration; could be wherever you setup doc store
public RavenDbRegistry(string connectionStringName)
{
  ...
  var generator = new MultiTypeHiLoKeyGenerator(documentStore, 32);
  documentStore.Conventions.DocumentKeyGenerator = entity =>
  {
      var special = entity as IGenerateMyId;
      return special == null ? generator.GenerateDocumentKey(documentStore.Conventions, entity) : special.GenerateId();
  };
  ...
}

public class Registration : IGenerateMyId
{
  public string CompanyId { get; set; }
  ...
  public static string FormatId(string companyId)
  {
      var result = string.Format("{0}/registration/", companyId);
      return result;
  }
  public string GenerateId()
  {
      return FormatId(CompanyId);
  }
  ...
}

public class RegistrationController : RavenController
{
	public ActionResult Index(string id)
	{
    //assuming id is the company id
    //this LoadStartingWith is an extension method i'm using with 960
		var registrations =
			RavenSession
				.LoadStartingWith<Registration>(Registration.FormatId(id)); 
        
  ...
}