Were any composites used on the A340 series?
Yes!!

The slide shows that composite are used in rear pressure bulkhead and keel beam in addition to other parts.


Source: https://company.airbus.com/dam/assets/airbusgroup/int/en/investor-relations/documents/2008/presentations/GIF2008/gif2008_workshop_composites_hellard.pdf

You can read more:
http://www.lcc.mw.tum.de/fileadmin/w00bkg/www/PDF/Symposium/LCC_Symposium_Havar.pdf