I think I got it. If I use an anonymous block manually what you suggested in your first example and I use F9 to run it, the output will be generated on Data Grid tab. I was looking for it on PL/SQL Result tab.
If i use F11 on my procedure tab, I get the pop-up, but I think there are errors with the generated script. I send the script and the stored procedure to you, offline.
T.