Eclipse: How to change default markup language for WikiText Editor

Question

I want to have project documentation in wiki format and commit to version control system together with code. I have tried standard Eclipse Mylyn WikiText Editor, which is sufficient for my needs.

Due personal preferences I have chosen Confluence markup language (another five or so are supported), but don't know how to change default markup language for newly opened files, they are opened with Textile markup language, so I have to manually switch to Confluence in popup menu.

When files have .confluence extension it works, but I want to have .wiki extension for my files.

There are some configuration options in Preferences, I have tried adding extension to content type, changing editors for extension, but without success. Eclipse Mylyn documentation says that default markup language can be changed for Mylyn Task Repository, but in my case I use WikiText Editor for files in project, without any task repositories.