It's explained in the manual:

Please keep the ideas coming! I appreciate any feedback. However, there might be restrictions on the iOS platform that I cannot work around.

Added in Textastic 4.0.

Textastic 4.0 now does support symbolic links.

Is that even possible?

Yes, this is explained in the manual: http://www.textasticapp.com/v4/manual/lessons/How_can_I_add_my_own_syntax_definitions__themes_and_templates.html

According to Wikipedia (http://en.wikipedia.org/wiki/ASCII), "Windows 1252" is also known as "ANSI". So try the "Western (Windows Latin 1, CP 1252)" encoding.

I was talking about when you are on the road, far away from your iPad. There are also people who don't have an iPad. :)

Reading the discussion, I might be wrong. Can you please enable the "Debug Log" setting in the connection's settings, try to connect again and send the log file to support@textasticapp.com?