diff --git a/library/Director/Objects/IcingaCommandArgument.php b/library/Director/Objects/IcingaCommandArgument.php
index be4db155..5de6d235 100644
--- a/library/Director/Objects/IcingaCommandArgument.php
+++ b/library/Director/Objects/IcingaCommandArgument.php
@@ -48,7 +48,8 @@ class IcingaCommandArgument extends IcingaObject
         // No log right now, we have to handle "sub-objects"
     }
 
-    public function replaceWith(IcingaObject $object)
+    // Preserve is not supported
+    public function replaceWith(IcingaObject $object, $preserve = null)
     {
         $this->setProperties((array) $object->toPlainObject(
             false,
diff --git a/library/Director/Objects/IcingaObject.php b/library/Director/Objects/IcingaObject.php
index b7e5da44..e4a467e3 100644
--- a/library/Director/Objects/IcingaObject.php
+++ b/library/Director/Objects/IcingaObject.php
@@ -339,6 +339,15 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
             }
         }
 
+        if (substr($key, 0, 5) === 'vars.') {
+            $var = $this->vars()->get(substr($key, 5));
+            if ($var === null) {
+                return $var;
+            } else {
+                return $var->getValue();
+            }
+        }
+
         if ($this->hasRelation($key)) {
             if ($id = $this->get($key . '_id')) {
                 $class = $this->getRelationClass($key);
@@ -1495,9 +1504,21 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
         return static::create((array) $plain, $connection);
     }
 
-    public function replaceWith(IcingaObject $object)
+    public function replaceWith(IcingaObject $object, $preserve = null)
     {
-        $this->setProperties((array) $object->toPlainObject());
+        if ($preserve === null) {
+            $this->setProperties((array) $object->toPlainObject());
+        } else {
+            $plain = (array) $object->toPlainObject();
+            foreach ($preserve as $k) {
+                $v = $this->$k;
+                if ($v !== null) {
+                    $plain[$k] = $v;
+                }
+            }
+
+            $this->setProperties($plain);
+        }
         return $this;
     }
 
diff --git a/test/php/library/Director/Objects/IcingaHostTest.php b/test/php/library/Director/Objects/IcingaHostTest.php
index 942a6639..ccf7a584 100644
--- a/test/php/library/Director/Objects/IcingaHostTest.php
+++ b/test/php/library/Director/Objects/IcingaHostTest.php
@@ -84,6 +84,73 @@ class IcingaHostTest extends BaseTestCase
         );
     }
 
+    public function testPropertiesCanBePreservedWhenBeingReplaced()
+    {
+        if ($this->skipForMissingDb()) {
+            return;
+        }
+
+        $db = $this->getDb();
+        $this->host()->store($db);
+        $host = IcingaHost::load($this->testHostName, $db);
+
+        $newHost = IcingaHost::create(
+            array(
+                'display_name'  => 'Replaced display',
+                'address'       => '1.2.2.3',
+                'vars'          => array(
+                    'test1'     => 'newstring',
+                    'test2'     => 18,
+                    'initially' => 'set and then preserved',
+                )
+            )
+        );
+
+        $preserve = array('address', 'vars.test1', 'vars.initially');
+        $host->replaceWith($newHost, $preserve);
+        $this->assertEquals(
+            $host->address,
+            '127.0.0.127'
+        );
+
+        $this->assertEquals(
+            $host->{'vars.test2'},
+            18
+        );
+
+        $this->assertEquals(
+            $host->vars()->test2->getValue(),
+            18
+        );
+
+        $this->assertEquals(
+            $host->{'vars.initially'},
+            'set and then preserved'
+        );
+
+        $this->assertFalse(
+            array_key_exists('address', $host->getModifiedProperties()),
+            'Preserved property stays unmodified'
+        );
+
+        $newHost->set('vars.initially', 'changed later on');
+        $newHost->set('vars.test2', 19);
+
+        $host->replaceWith($newHost, $preserve);
+        $this->assertEquals(
+            $host->{'vars.initially'},
+            'set and then preserved'
+        );
+
+        $this->assertEquals(
+            $host->get('vars.test2'),
+            19
+        );
+
+
+        $host->delete();
+    }
+
     public function testDistinctCustomVarsCanBeSetWithoutSideEffects()
     {
         $host = $this->host();