problem with portfolio pagination

Hello
http://www.l2gshop.com/progettazione-ambienti/
i have created this portfolio page with filter option and 9 item for page.
but the filter work separatly for each page and not with all items.
so in first page i have some categories and in second page i have other categories
i must use -1 for have all categories but so if i have 100 items i have a very long and havvy page!

regards
Francesco