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Can you please send an example file with demonstrates the problem to support@textasticapp.com? I can't reproduce it.
You can download the manual as a PDF file from http://www.textasticapp.com/v4/manual/textastic_manual.pdf  and use iBooks or another PDF reader to read it on your iPad.
The next version will allow you to import pictures from the Photo library.
The next version will support zip and unzip.

You could try to use the "ASP vb.NET" syntax highlighting definition. You can select this definition in the File Properties popover after you opened the file. 

It looks interesting, but judging by the Readme, it probably won't support many real life configurations - i.e. modern authentication methods. Also, the last library change was a year ago.
It's great to hear that it's working for you now.
Is your key file protected by a pass phrase? You need to enter the pass phrase in the password field below the user name. 
Es gibt eine alte Version des Handbuchs auf deutsch unter http://www.textasticapp.com/de/manual/

Allerdings wird dies nicht weiter gepflegt und enthält weniger Einträge.