XML export uses HTML escaping instead of XML escaping, which causes problems

Subject says it all.

In addition, from a user:

we use jira 2.6.1 and discovered some problems with german "umlauts"
when exporting issues to XML which have some german "umlauts" in one of
the custom fields.
See the error attached.

Cheers,
Stefan

XML Parsing Error: undefined entity "uuml"
Location:
http://jira:9980/secure/IssueNavigator.jspa?view=rss&pid=10000&types=7&sorter/field=issuekey&sorter/order=DESC&tempMax=25&reset=true&decorator=none
Line Number 126, Column 77: