Here's the documentation for the x-callback-url actions that will be supported in Textastic 4.4:

http://www.textasticapp.com/v4/manual/x-callback-url.html

An update is currently in review at Apple. It will be available as soon as it is approved.

will be changed in the next update

Support for .scss and .sass syntax highlighting will be included in the next update.

A new document is untitled. You are asked for a file name when you save it the first time (using Cmd-S for example).

When you save a new file, you can choose iCloud as the destination in the "Where" dropdown.

You can also use the File -> Move To... command to move a file to iCloud.

Or you can move your mouse cursor over the file name in the window title bar, click on the triangle that appears next to the file name and choose "Move to iCloud...".

If you open the File menu and press the Alt key on your keyboard, the "Duplicate" command becomes "Save As...".

So there are many ways to save, move or copy a file to iCloud.