I will assume you are doing this on a usb.
go to your usb wwe 13 ch folder and rename ch317 to -ch317.pac
now copy your newly created layla pac to that usb wwe 13 ch pac folder
now open up xpacker and locate that newly added ch317 folder containing layla and do the arch update to both archs files.
then you are done.
the update has to be done within the folder where you wwe13 ch files are stored for it to work.
go to your usb wwe 13 ch folder and rename ch317 to -ch317.pac
now copy your newly created layla pac to that usb wwe 13 ch pac folder
now open up xpacker and locate that newly added ch317 folder containing layla and do the arch update to both archs files.
then you are done.
the update has to be done within the folder where you wwe13 ch files are stored for it to work.