Custom Data not included in $objectRef passed to hooks

Steps to reproduce:

1.) Create a Custom Data set for Individuals which accepts multiple values
2.) Implement hook_civicrm_post with something like if ($objectName == 'Individual' && $objectId && ($op =='create' || $op =='edit'))

{ print_r($objectRef); }

3.) In CiviCRM, click the 'Edit' link for an Individual. Enter data in custom fields.

Result: The data in custom fields is not contained in the output $objectRef