IDOC AEX and messages in Delivering and "To Be Delivered"

Hi

We are on a dual stack PI 7.3.1 sp6 and we have seen lately that some messages are placed in the status "To Be Delivering" and Delivering.

Currently the only way we have to restart the messages is to restart the J2EE server. Which is not a good way to get messages processed on in a productive system.

Any pointer to how We can get the messages restarted?