A question if I may

Dear Madam/Sir,

I have encountered very painful problem regarding XML. I am a programmer and
I now try to build a file containing all the required information to be
later read by a
Java parser.  The product specification need to meet any platform.
I tried looking at archives of many XML newsgroups and wandered around in
some of the sites without any good luck.
I have a major problem with quotes and I am afraid it will enhanced later to
something that might cause a general failure.

" seems to replace quotes - BUT it appears to be accepted only on
certain platforms and not on others.

Could you please clear this with all the ISO versions? What standard should
I use or support?
And most important  : What it the charset that accepts the broadest
variations of chars?

www.stg.brown.edu/~sjd/chartables.htr  says something about ISO 646. what is
the TEI subset? EPI?
XML seems to be very good and simple but the references piled to something
enormous .
Please please please if possible to redirect me to something in this matter
that will resolve the mystery.



Thank you before hand,

Elizabeth Katz