Magic Fields 2 also has an additional MySQL table – wp_mf_post_meta – to store data for its meta fields so you need to add a corresponding row to this table also. The columns in the entry are simple enough:
mysql> show columns from wp_mf_post_meta;
+-------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------+--------------+------+-----+---------+-------+
| meta_id | int(11) | NO | PRI | NULL | |
| field_name | varchar(255) | NO | | NULL | |
| field_count | int(11) | NO | | NULL | |
| group_count | int(11) | NO | | NULL | |
| post_id | int(11) | NO | MUL | NULL | |
+-------------+--------------+------+-----+---------+-------+
5 rows in set (0.01 sec)