[OAI-implementers] valid character encoding

[Todd White]

is there a limited number of valid character encodings for a valid OAI
repository?

the encoding i am using is "ISO-8859-1"  this is to support some special
characters in our metadata that were not supported by UTF-8.

when i tested our newly developed OAI respository software using the
web-based Open Archives Initiative - Repository Explorer
(http://oai.dlib.vt.edu/cgi-bin/Explorer/oai2.0/testoai) it told me...

  XML Schema Validation Error !
  Illegal character encoding in XML

here's the URL to our repository:
  http://michiganteacher.net/oai