Ive noticed this also as i have created several packs (viewtopic.php?f=23&t=3332) that are no longer showing up in the store. i also put them in the user/packs, i also tried putting them in the core.zip file but i end up with a bsod-ish.
i created new ones.There are packs of 360 cards from each block and also from core releases.Maybe should be fix in another version?.I'll try to compile the last svn source...