Your comments

I thought a lot about this when implementing the quick upload feature.

In my opionion the override alert should stay:
The uploading option only appears if you are working with a file downloaded from a FTP or Dropbox server. If you didn't, the first option will be to mail the file.

So, if you accidentally tapped on the upload action, this is your last change to prevent overwriting a remote file. This can be a destructive process on a live web server, so Textastic warns the user.
You need to select the correct virtual on-screen keyboard layout corresponding to the connected hardware keyboard. (see comments)
No problem. Maybe it will be helpful to other people. :)
The keyboard layout is provided entirely by the iOS system. Did you try to use your keyboard in another app (like Notes)?

You need to select the correct virtual keyboard for your hardware keyboard. So, if your hardware keyboard is French, you have to tap on the "Globe" icon on the virtual on-screen keyboard to select the corresponding French keyboard layout.

There is also a problem with accented characters in Textastic 2.0 that might be problematic for you when you want to type French words: http://feedback.textasticapp.com/feedback/15340-wrong-behaviourcrash-when-entering-accented-characters-using-a-hardware-keyboard/
What exactly are you trying to do? You can open .xsd files in Textastic, can't you?
Sorry, but I need a lot more information in order to find out why it would crash:

When exactly does the crash happen? When retrieving the file information? When downloading files? When downloading a particular file?

Since 400 files is quite a lot (although this has been tested with a lot more files), this could possibly be an issue with low memory: did you try to restart your device before attempting the download?

Did you try to download only part of the files/folders and not all of the 400 files? Did it work?

Can you download other files/folders on the same server? If not: which ftp server software is it running?
Thanks, I tried one of the sample files and see what you mean. The problem is that I haven't found a way to set the MIME type for the UIWebView and still have it recognize relative files (like css and images).

My workaround was to add a "html" extension to the file as UIWebView seems to interpret the file extension. I thought, it would recognize SVG files by their content, but it doesn't.

So, right now I don't know how I can set the correct mime type for SVG files without breaking the preview function for normal html files with css and images files relative to them... :(
This is fixed for the next update.

In the meantime, you can use the virtual on-screen keyboard to enter accented characters (like á or ñ). Sorry for the inconvenience.
Well, you can first download the file from your Dropbox to the local file storage of your iPad.

Then connect to the FTP server and upload the file.

So yes, this is possible.
Sorry, but the order is determined by iOS, so unfortunately, this is not possible. (At least I'm not aware of it).