At least in the PC (and OS-X) version all the runes have specific properties, see
http://www.grimrock.net/2011/10/14/magic-and-runes/
Thus the spells for enchanting arrows all follow the same simple pattern: the runes form an arrow to the left (Life, Physicality, Death), with the addition of the rune for the specific element to enchant the arrow with.
For that reason I doubt that it is possible at all to enchant arrows at all, as a new combination of runes would be "illogical" within the system of runes: there is no way of linking each of the four elements with the same set of runes, taking into account that spells now can only be created from adjacent rooms.
Maybe somebody can confirm that there scrolls for Enchant Arrow can not be found in the locations known from the PC version?