Hello Ian, Can I point you to some people that has already done something similar? christiane.boehner at jrc.it bye, ^angela ^=^=^=^=^=^=^=^=^=^=^=^=^=^=^=^=^=^ ^Angela Guimaraes Pereira Joint Research Centre - TP650 21020 Ispra (VA) Italy Tel. +39 332 785340 Fax. +39 332 789394 e-mail: angela.pereira at jrc.it o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o