Sorry, we missed that one for 3.1. It's actually highlighted on the list of bugs to be fixed for the next version though so we will be adding it. To be honest it should have gone in for 3.0 and it was only that we missed it amongst the deluge of other things we had to do.
The function alter trigger will be available in final 3.1?
Not a critical trouble, just to know about it.
Thanks
Ésio