Advancedsettings.xml more info and location:
For more information about advancedsettings.xml see this wiki page
Advancedsettings.xml does not exist so you have to create it in the location shown below.
Back Button (instant Replay):
Back Button rewind 5 seconds (instant Replay action):
while playing a video or movie you can skip back five seconds in case you missed something instead of going back to the main video or library view, If you just switched from the XBOX's XBMC then you will know what I am talking about, you will be happy to know if you want to make the Back button act in windows like the way it did on the XBOX then follow the steps below: Thanks to ExGemini for reminding me about it :-)
edit advancedsettings.xml with XML Marker and make sure you have this code in it, after finishing save and exit XML Marker.
you can change "5" to any value you want, XBMC default is "7" seconds.
Now Edit Keyboard.xml to finish the job off:
Right click on Keyboard.xml and select Edit with XML Marker.
1- on XML Marker left navigation window click on the "+" against "keymap"
2- from the dropdown tree look for "FullscreenVideo" click on it
3- Now the right side will be highlighted look for
4- change it to
Note: back button will still function like normal outside the Full sceen video
Save and Exit.