hook civicrm_tokens is never implemented when emailling contribution receipt

I'm implementing a hook token module, but doesnt seem to be working, based on http://civicrm.org/node/637

In my message template for memberships ive added "hello {$test.hello}" to both online and offline

I can see the function is being called because /tmp/tokens.txt gets created when i purchase a new Membership Contribution,

function civi_custom_membership_civicrm_tokens( &$tokens ) {
$tokens['test'] = array( 'test.hello' );
}

function civi_custom_membership_civicrm_tokenValues( &$values, &$contactIDs, $jobID ) {

if ( is_array( $contactIDs ) ) {
$contactIDString = implode( ',', array_values( $contactIDs ) );
$single = false;
foreach ($contactIDs as $contact)

{ $values[$contact]['test.hello']= "Hello world!"; }

} else

{ $single = true; $values['test.hello'] = "Hello world!"; }

file_put_contents("/tmp/token.txt","was ran");
}