I actually tried that at first, but the Typo-flavored Textile in my old posts wasn't reliably interpreted by Pandoc. (That's also why I had to clean up the posts after I used Pandoc to convert them into Markdown.) Since I had manual edits to do in any case, I figured I might as well do them after I converted my posts to Markdown since it seems to be the Pandoc's best-supported markup language.