Can't escape the escape string

I have the following use case in a XML file:

    <variable name="xwikiDataDir" value="%APPDATA%\XWiki\${project.version}\data" condition="windowsSevenAndGreater"/>

Before 3.0 it used to produce

    <variable name="xwikiDataDir" value="%APPDATA%\XWiki\8.2\data" condition="windowsSevenAndGreater"/>

\ is now the default escape character, I'm fine with that but then it should be possible to escape the escape string which is buggy right now.

The following source

    <variable name="xwikiDataDir" value="%APPDATA%\XWiki\\${project.version}\data" condition="windowsSevenAndGreater"/>

gives me

    <variable name="xwikiDataDir" value="%APPDATA%\\XWiki\8.2\data" condition="windowsSevenAndGreater"/>

Notice the still doubled \. The first one should be removed from the result.

I tried escapeWindowsPaths bu it does not seems to be matching my string as a Windows path which is probably another bug.

Since I can't find any way to disable escaping (see MRESOURCES-231),
I ended up finding a character I don't have in my file and set it as escapeString.