I have been working on creating a font for Brahmi. I have add the necessary glyph imported through font creator. I am now working on creating the opentype rules for the font rendering. I am using VOLT to create the opentype rules. It is just a simple ligature substitution, without any complex mark re-ordering stuff.
Since, Brahmi is not yet supported in Windows, I have used Latin as the default script, and added the ligature substitution. Even while proof reading, the
substitution worked.
But I installed the font, and checked it out. The ligature was not formed.
(U+11013, U+11038) [I am not able to post the actual SMP characters. The phpBB is throwing a sql error

Assuming SMP wouldn't be supported, I mapped the characters to Tamil. And assigned the script tag as Tamil in VOLT, and creating the opentype substitution rules. Even, then the ligature wouldn't form, even though proof reading windows in VOLT formed the ligature well.
கா(U+0B95, U+00BE)
Then, I proceeded to map the character to the Latin plan, with the script tag as Latin. And bingo the ligature got formed !
ka (U+0061, U+006B)
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When ligatures are getting formed with Latin code points, why is not getting formed for Tamil or Brahmi ?
Am I missing here something ?
I have attached the font files (with workign VOLT tables).
I would be very grateful to receive any guidance and support regarding this.
V