diff --git a/hosting_sync/README.md b/hosting_sync/README.md
new file mode 100644
index 0000000..05a0d07
--- /dev/null
+++ b/hosting_sync/README.md
@@ -0,0 +1,29 @@
+Hosting Sync
+============
+
+Lets a user sync database and files from one site to another.
+
+
+Custom Alias
+------------
+
+You can also specify a custom alias, one not managed by Aegir, for a sync task.
+
+
+A minimal example could be:
+```php
+<?php
+
+$aliases['live'] = array(
+  'remote-host' => 'server.domain.com',
+  'remote-user' => 'www-admin',
+  'root' => '/other/path/to/drupal',
+  'uri' => 'http://example.com',
+
+  'context_type' => 'site',
+  'server' => '@server_master',
+);
+```
+
+Only the last two lines are added for compatibility with hosting_sync.
+See the Drush documentation for more options.
diff --git a/hosting_sync/hosting_sync.tasks.inc b/hosting_sync/hosting_sync.tasks.inc
index 227298c..b297040 100644
--- a/hosting_sync/hosting_sync.tasks.inc
+++ b/hosting_sync/hosting_sync.tasks.inc
@@ -206,6 +206,28 @@ function _hosting_sync_sites_elements($node, $result, $parents) {
       );
     }
   }
+  $elements['custom_alias'] = array(
+    '#type' => 'fieldset',
+    '#title' => "A custom Drush alias",
+    '#attributes' => array('class' => array('hosting-sync-platform-group')),
+  );
+  $elements['custom_alias']['radio'] = array(
+    '#type' => 'radio',
+    '#title' => 'Any Drush alias defined on the hostmaster server.',
+    '#parents' => $parents,
+    '#return_value' => 'CUSTOM',
+  );
+  $elements['custom_alias']['text'] = array(
+    '#type' => 'textfield',
+    '#title' => "",
+    '#parents' => $parents,
+      '#states' => array(
+        // Only visible this field when backups is enabled.
+        'visible' => array(
+          ':input[name="parameters[source]"]' => array('value' => 'CUSTOM'),
+        ),
+      ),
+  );
 
   return $elements;
 }