Pierre,
I don't have the especifics for this case, but in general you could try to swallow the event and programm your own dialog. To swallow the event you just return any other value than 0 in the callback function.
By swallowing the event the control will not nottice that the user clicked or changed a value, thus it won't show de default dialog.
I hope this helps, otherwise let me know if you have other questions.
Regards,
Juan Carlos
N.I.