[XeTeX] combine 2 glyphs with xelatex

[François Patte]

Bonjour,

I would like to combine glyphs using xelatex : the glyphs are: U+0947 
and U+093D if I write \symbol{"0947}\symbol{"093D}, I get the two glyphs 
side by side, the first one with a dotted circle below.

What I want is the first one combined with the second one ie. the first 
one above the second one.

How can I get this result?

Thank you.

-- 
François Patte
UFR de mathématiques et informatique
Laboratoire CNRS MAP5, UMR 8145
Université Paris Descartes
45, rue des Saints Pères
F-75270 Paris Cedex 06
Tél. +33 (0)6 7892 5822
http://www.math-info.univ-paris5.fr/~patte
FSF
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