[XeTeX] makeindex and active characters

[musa furber]

I am indexing a book that has several dozen words with diacritics.  
The list includes upper and lower case forms of āīū, ḍḥṣṭẓ.

  When I use LaTeX and utf8x encoding, the index processes without a  
problem.

When I switch to XeLaTeX I get errors every time one of  
ḍḥṣṭẓ is encountered. I declared those characters active  
characters so that I can provide the glyphs even though they are  
missing in my main font (Minion). For example, I have declarations like

"""
\catcode"1E0C=\active \def^^^^1e0c{{\transfont\string Ḍ\normalfont 
\selectfont}}
"""

When I look at the .idx file, I found lots of pieces of the active  
character code:

"""
\indexentry{Hanafi@{\transfont  {\protect \protect \edef cmr 
{jMinionProRegular(0)}\protect \afterassignment \edef 10.95{-1} 
\afterassignment \edef 13.6pt{13.6pt}\edef 1{}\let 1\def \size at update  
{\baselineskip 13.6pt\relax \baselineskip 1\baselineskip  
\normalbaselineskip \baselineskip \setbox \strutbox \hbox {\vrule  
height.7\baselineskip depth.3\baselineskip width\z@ }\let  
\size at update \relax }\xdef \OT1/cmr/m/n/7 {\OT1/cmr/m/n/10.95 }\OT1/ 
cmr/m/n/7 \size at update \enc at update Ḥ\protect \protect \edef OT1{U} 
\let \enc at update \relax \protect \edef cmr{cmr}\protect \edef m{m} 
\protect \edef n{n}\protect \afterassignment \edef 10.95{-1} 
\afterassignment \edef 13.6pt{13.6pt}\edef 1{}\let 1\def \size at update  
{\baselineskip 13.6pt\relax \baselineskip 1\baselineskip  
\normalbaselineskip \baselineskip \setbox \strutbox \hbox {\vrule  
height.7\baselineskip depth.3\baselineskip width\z@ }\let  
\size at update \relax }\xdef \OT1/cmr/m/n/7 {\OT1/cmr/m/n/10.95 }\OT1/ 
cmr/m/n/7 \size at update \enc at update \ignorespaces \relax \protect  
\afterassignment \edef 10.95{-1}\afterassignment \edef 13.6pt{13.6pt} 
\edef 1{}\let 1\def \size at update {\baselineskip 13.6pt\relax  
\baselineskip 1\baselineskip \normalbaselineskip \baselineskip  
\setbox \strutbox \hbox {\vrule height.7\baselineskip depth.3 
\baselineskip width\z@ }\let \size at update \relax }\xdef \OT1/cmr/m/n/ 
7 {\OT1/cmr/m/n/10.95 }\OT1/cmr/m/n/7 \size at update \enc at update } 
\normalfont  \selectfont  }anafī}{8}
"""

Is there any way to suppress the expansion of the active characters  
just when index entries are written?

Thanks,
Musa