This bug previously prevented us from using 2.0-beta-9 (our checkin policy requires issues in commit messages). There are other bugs in 2.0-beta-8, but previously it was the most workable.
MRELEASE-526 prevents us from using 2.0.
However, this plugin configuration seems to work. It uses scm 1.3, and seems to solve this issue:
<!-- Per http://jira.codehaus.org/browse/MRELEASE-442, scmCommentPrefix should work for release-plugin 2.0-beta-9
if scm 1.3 is used. -->