Problem solved! I've checked the .NET installation with the .NET Framework Setup Verification Tool http://blogs.msdn.com/b/astebner/archive/2008/10/13/8999004.aspx and I've verified that I didn't install it properly.
I've installed the MSXML3 and changed the OS to WinXP ( https://wiki.archlinux.org/index.php/Wine#Installing_.NET_Framework_4.0 ) and now NET.isNETSupported gets value 1
