E9.1 Set Sequencing on GRID



i'm currently working on a customization of a P0411, among all the other requirements, there is a request to sort grid data in a custom way.
I never had the needs of use "Set Sequencing" system function, but i wouldn't expect so much trouble.

I'm testing its functionality and i'm unable to make it work. Reading the manual seems button clicked event on find should do the trick (there is no clear sequencing anywhere) simply as follow:


(this is just an example i need to work on other columns)
AN8 is ignored, the others are the standard sort order of the grid as you may well know.

I started trying on Dialog Is Initialized, moved to Push Button Find and even tried on Post Dialog is Initialized.

Anybody out there has some hint on this system function?

Thanks a lot!