BUMP. Did you ever figure this out? I would really like to know as well.

 

I don't have my phone with me to double check, but what I do is open the attachment, once I am looking at it (usually a picture), tap the screen. At the bottom of the screen there should be a pause button, you can click on it to stop the 5 second timer. You can also click the other icon to save the picture.

Like I said before, I don't have my phone to double check, but I "think" once you have the photo paused, you can hit menu and change the settings on how long you want the timer to last.