The atm only way to interact with scheduled/delayed messages, the JobSchedulerView mbean, does not provide a way to get or delete messages that match a specific selector, e.g. something that behaves similar to the Session.createBrowser(queue, messageSelector) method.
This means that for instance in order to delete all scheduled messages with a specific custom property, one has to
1. get all messages (which might not even work as the mbean doesn't stream)
2. determine if the mbean matches the selector locally and if then hit the removeJob(id) mbean operation
which is really inefficient.