Immediate notifications with Ajax

The "immediate sending" option in Notifications module (see Clipboard01.png) allows the notifications to execute right away. But with Ajax, this doesn't work, and notifications aren't sent until the next cron. Moreover, in some cases the cron for subscriptions/notifications also fails (I wasn't able to identify when/how/why).

_{this is also on the Ajax issues: http://drupal.org/node/444004}