I know i have to set...
Code:
  [Setup]
  UpdateUninstallLogAppName=no
  UsePreviousAppDir=yes
  CreateUninstallRegKey=no
  ;...
And, As I didn't set an AppId in my Application install package, now I set AppId=MyAppName, this way this update package should find the Application folder.
I know that because of this: Update Install , but..
The problem:
When I try to compile this update package, Inno setup says "DefaultDirName" REQUIRED. I can't add a defaultdirname, because the user shouldn't select an install location, this update should be automatically installed where the application had been installed.

Any ideas?

Thanks.