diff --git a/lib/Model.php b/lib/Model.php
index 99667b41f..03a01f2af 100644
--- a/lib/Model.php
+++ b/lib/Model.php
@@ -1291,7 +1291,9 @@ public function reload()
 
 	public function __clone()
 	{
-		$this->__relationships = array();
+		$this->__relationships = array_map(function($rel) {
+			return clone($rel);
+		}, $this->__relationships);
 		$this->reset_dirty();
 		return $this;
 	}
diff --git a/lib/Relationship.php b/lib/Relationship.php
index 9846b44a4..61b80ea5e 100644
--- a/lib/Relationship.php
+++ b/lib/Relationship.php
@@ -291,7 +291,7 @@ protected function set_class_name($class_name)
 		if (!has_absolute_namespace($class_name) && isset($this->options['namespace'])) {
 			$class_name = $this->options['namespace'].'\\'.$class_name;
 		}
-		
+
 		$reflection = Reflections::instance()->add($class_name)->get($class_name);
 
 		if (!$reflection->isSubClassOf('ActiveRecord\\Model'))
@@ -507,7 +507,7 @@ public function load(Model $model)
 				$fk = $this->foreign_key;
 
 				$this->set_keys($this->get_table()->class->getName(), true);
-				
+
 				$class = $this->class_name;
 				$relation = $class::table()->get_relationship($this->through);
 				$through_table = $relation->get_table();
@@ -604,7 +604,7 @@ public function create_association(Model $model, $attributes=array(), $guard_att
 	public function load_eagerly($models=array(), $attributes=array(), $includes, Table $table)
 	{
 		$this->set_keys($table->class->name);
-		$this->query_and_attach_related_models_eagerly($table,$models,$attributes,$includes,$this->foreign_key, $table->pk);
+		$this->query_and_attach_related_models_eagerly($table,$models,$attributes,$includes,$this->foreign_key, $this->primary_key);
 	}
 }
 
@@ -685,6 +685,9 @@ public function load(Model $model)
  */
 class BelongsTo extends AbstractRelationship
 {
+
+	static protected $valid_association_options = array('primary_key');
+
 	public function __construct($options=array())
 	{
 		parent::__construct($options);
@@ -695,6 +698,9 @@ public function __construct($options=array())
 		//infer from class_name
 		if (!$this->foreign_key)
 			$this->foreign_key = array(Inflector::instance()->keyify($this->class_name));
+
+		if (!isset($this->primary_key) && isset($this->options['primary_key']))
+			$this->primary_key = is_array($this->options['primary_key']) ? $this->options['primary_key'] : array($this->options['primary_key']);
 	}
 
 	public function __get($name)
@@ -727,4 +733,4 @@ public function load_eagerly($models=array(), $attributes, $includes, Table $tab
 	{
 		$this->query_and_attach_related_models_eagerly($table,$models,$attributes,$includes, $this->primary_key,$this->foreign_key);
 	}
-}
\ No newline at end of file
+}
diff --git a/test/RelationshipTest.php b/test/RelationshipTest.php
index 957016c65..ccea4073a 100644
--- a/test/RelationshipTest.php
+++ b/test/RelationshipTest.php
@@ -23,7 +23,7 @@ public function set_up($connection_name=null)
 		Venue::$has_one = array();
 		Employee::$has_one = array(array('position'));
 		Host::$has_many = array(array('events', 'order' => 'id asc'));
-		
+
 		foreach ($this->relationship_names as $name)
 		{
 			if (preg_match("/$name/", $this->getName(), $match))
@@ -80,7 +80,7 @@ public function test_has_many_basic()
 	{
 		$this->assert_default_has_many($this->get_relationship());
 	}
-	
+
 	public function test_eager_load_with_empty_nested_includes()
 	{
 		$conditions['include'] = array('events'=>array());
@@ -107,7 +107,7 @@ public function test_gh_256_eager_loading_three_levels_deep()
 
         $this->assertEquals('Yeah Yeah Yeahs',$bill_events[0]->title);
     }
-	
+
 	/**
 	 * @expectedException ActiveRecord\RelationshipException
 	 */
@@ -165,6 +165,19 @@ public function test_belongs_to_with_explicit_foreign_key()
 		Book::$belongs_to = $old;
 	}
 
+	public function test_belongs_to_with_explicit_primary_key()
+	{
+		$old = Book::$belongs_to;
+		Book::$belongs_to = array(array('explicit_author', 'class_name' => 'Author', 'primary_key' => 'parent_author_id'));
+
+		$book = Book::find(1);
+		$this->assert_equals(1, $book->author_id);
+		$this->assert_equals(1, $book->explicit_author->parent_author_id);
+		$this->assert_equals(3, $book->explicit_author->author_id);
+
+		Book::$belongs_to = $old;
+	}
+
 	public function test_belongs_to_with_select()
 	{
 		Event::$belongs_to[0]['select'] = 'id, city';
@@ -423,6 +436,23 @@ public function test_has_many_with_explicit_keys()
 		Author::$has_many = array(array('explicit_books', 'class_name' => 'Book', 'primary_key' => 'parent_author_id', 'foreign_key' => 'secondary_author_id'));
 		$author = Author::find(4);
 
+		$this->assert_equals(2, count($author->explicit_books));
+
+		foreach ($author->explicit_books as $book)
+			$this->assert_equals($book->secondary_author_id, $author->parent_author_id);
+
+		$this->assert_true(strpos(ActiveRecord\Table::load('Book')->last_sql, "secondary_author_id") !== false);
+		Author::$has_many = $old;
+	}
+
+	public function test_has_many_with_explicit_keys_and_eager_loading()
+	{
+		$old = Author::$has_many;
+		Author::$has_many = array(array('explicit_books', 'class_name' => 'Book', 'primary_key' => 'parent_author_id', 'foreign_key' => 'secondary_author_id'));
+		$author = Author::find(4, array('include' => 'explicit_books'));
+
+		$this->assert_equals(2, count($author->explicit_books));
+
 		foreach ($author->explicit_books as $book)
 			$this->assert_equals($book->secondary_author_id, $author->parent_author_id);