Hi i would like to have hint about something probably not to hard to accomplish but now i have no idea how to reach it.
It is the same way as Attachment in form...
But in a Button i want the user select an external file (likes pdf or other) and onces its set the button push will open the file... and not ask again for setting another files.. Maybe for practical aspect a secondary button can change the setting in case of wrong files set ..
One way of doing it is by opening an input file dialog for a file storage field. Execute that when the file storage field is empty. To delete the attached file, clear the file storage field. Hope that helps.