Custom fields... i need =

[landero]

hi all, i'm newbie and i don't speak english very well, i'm italian.
well..

an easy example... i have 1 customfield with 5 propriety (SIZE)

1° size = 100 €
2° size = 400 €
3° size = 800 €
4° size = 900 €
5° size = 1100 €

the product start cost 100 €
for select 2° size i don't want insert +300
but i want insert =400
how in previous version...

url my site example
http://www.spaziomaterassi.it/prodotti/materassi/materassi-a-molle/export-detail

url site inspirator
http://www.flex-system.it/prodotti/6-materasso-a-molle-extra-lusso.asp


help me please!