ok, thanks for the info. I guess there's no way around that even if you have a jailbroke device?

Do you know of any other browsers that work around the sandbox issue?

I am having the same issue...I have imported a website (which works fine on my pc and android) with Working Copy onto my ipad (with the whole working directory) and I can open and edit it fine with Textastic but if I preview it. It won't see the CSS style sheets and I just see the plain HTML page. So I have to open it in iFile's browser, which is the only browser I have seen that works with a local css site.