Devanagari question

Namaste,
recently needing to do some work with Devanagari (Indian alphabet used
for Hindi and others), I of course want to use Tcl/Tk for that. I
however experience that the renderer on Windows XP that Tk uses fails
to do some things (like short-i to the left, consonant clusters
without vertical), while another renderer that seems to be used in
Internet Explorer, Wordpad and Outlook does things right - example
word हिन्दी .
As I see that people from India are sometimes on this group, could
some of you advise? For persistence, I've also sketched the problem on
http://wiki.tcl.tk/3158 "bidi rendering".

Best regards, Richard
.