I use Textastic in combination with a small app that I open from within Textastic. The app uploads the file to a server, which processes the file and sends the results back to the app. From within the app I can switch back to Textastic. Changes I made to a file were reflected in the results. This was the case with IOS 5.1.1 on iPad 1. I recently switched to iOS 6.0.1 on iPad 4. Now it seems that Open In... from the toolbar button no longer works as before. Open In... from the list view seems to work, although it looks as if I have to wait a bit (10 seconds between saves?).
Customer support service by UserEcho