|mmm - Possibly a visit to Sony may discover them? They may agree to sell/send you a set?|
Equally a google trawl may bring them up I know that many are out there for the assorted makes (Acer etc...).
And finally (as per the late Walter Cronkite...) can you not make a set from the system as is? Usually there is (these days) an included util to this end on the installation as is; and one is often advised/encouraged to make a set as soon as one boots up and logs onto a new system successfully? This regardless of whether or not you are also supplied with a set as part of the orignal deal.