diff --git a/src/Builder/Builder.php b/src/Builder/Builder.php
index ba5572b..0fd579c 100644
--- a/src/Builder/Builder.php
+++ b/src/Builder/Builder.php
@@ -194,7 +194,12 @@ public function buildProperty($name, $values, $emptyIfMissing = false)
                         break;
 
                     case 'enum':
-                        // @todo: alter specials types
+                        if (is_numeric($value)) {
+                            $value = pack('N', $value);
+                        } else {
+                            // @todo: handle values for enum types from RFC 8011
+                            throw new CupsException('Non-numeric enum value not supported for : "'.$name.'".');
+                        }
                         break;
 
                     case 'range_of_integers':