input 39 in ansinew.def

[Peter Harmand <harmand@math.uni-oldenburg.de>]

Could somebody explain to me, why the input character 39 in ansinew.def
is left out and why the simple-minded approach
  \DeclareInputText{39}{\textquotesingle}
is not working?

I'm using my personal fontencoding (a corrected and completed version of
8renc.def, which defines \textquotesingle) and a font which contains
quotesingle -- so, IHMO, it's not a font encoding problem.

Any comments on the brute force solution?
\catcode`\'=\active \chardef'=31
%         ^                 ^  this is input character 39
% 31 in the position of quotesingle in 8r

Thanks in advance,
Peter.