UTF-8 encoding question regarding PhpPgAdmin development

Dear all,

We are working on PhpPgAdmin UTF-8 support. I would like to be able to view
UTF-8, ASCII and Latin1 databases in PhpPgAdmin without changing HTML header
encodings.

I guess this can be done using:
SET CLIENT_ENCODING='Unicode'
for all PhpPgAdmin connections.

My question are:

- Are some database encodings not translatable into UTF-8 using SET
CLIENT_ENCODING = 'Unicode'. It used to be the case for Latin1, but it has
been fixed now.

- Some letters, like the euro sign, do not belong to Latin1. Example:  let's
say we have a Latin1 database and use SET CLIENT_ENCODING = 'Unicode'. If I
input a euro sign, does it get rejected by PostgreSQL?

- More generaly, is it safe to convert an Encoding (ex: Latin1 or Chinese
multi-byte) into UTF-8 using SET CLIENT_ENCODING? Can all multi-byte
encodings be converted into/from UTF-8 safely?

Best regards,
Jean-Michel