[maven 3.x] configuration not recognized on <executions> level

I tried the example snippet from

http://maven.apache.org/plugins/maven-enforcer-plugin/usage.html

with enforcer plugin 1.0-beta-1 and maven 3.0-alpha-7.

It seems the enforcer configuration is only recognized if moved up to the <plugin> level.
<configuration> under <execution> is ignored. The plugin complains that no rules are configured.

This may be a general maven 3 bug ...

See example poms attached for reproducing the problem and an alternative pom with configuration on plugin level which works.

Also includes

mvn enforcer:enforce -X -e

output.

Regards
Jan