when those hackers got shells on your box, the lock doesnt help either, for me it was they did the ST variables, then the hacked the .htaccess files, well the list is endless you guys MUST cleanout your box first, if you dont do that in the first place you can lock whatever you want - it wont help
i was troubled with this hack more then anybody else, the only, and for me it was after 50+ hacks the only thing which worked permantley is to hire the cleanout package of the soft-com.biz guys, they charge 75$ one time fee for the cleanout and they keep monitoring your box for hacks for some time after it,