Are you looking to do this so your form shows instead
of the Advanced Form in some cases?
If on the other hand what you are trying to do is handle the normal Scheduler events to show your form under some conditions and the regular form under others, then the FormCreating
event is your friend.
Basically, you wire up the FormCreating event, test to see if the conditions are right for your custom form, if they are, set e.Cancel = true and call code to open your own form. If they aren't just let the Scheduler do it's thing.
Hope this helps. Sorry if I've misunderstood your requirements.