[kh99]

Function build_datastore() in includes/functions.php has a function build_datastore(). It has a parameter to automatically unserialize the data when it's read. You can arrange for your datastore item to be read back in (and unserialized) by adding it to $new_datastore_fetch[] at hook init_startup. If you want it only to be read in the admincp, you can check for VB_AREA == 'AdminCP'.

Just for the record, the settings are kept in the 'setting' table and automatically built in to the settings datastore item when they are edited. So I think another option might be to add your settings to the setting table but put a value for grouptitle that doesn't exist in the settinggroup table, then I think they won't be displayed. (But now that I think about it more, I'm not sure what the advantage of that would be.)