maven-release-plugin doesn't pass username to maven-scm-provider-cvs

The class CvsScmProvider refuses a CVS url without username. See, for example, line 253ff:

int index = userhost.indexOf( "@" );

if ( index == -1 )

{ result.messages.add( "The userhost part must be on the form: <username>@<hostname>." ); return result; }

On the other hand, the maven-release-plugin doesn't pass the full URL to the provider. In AbstractReleaseMojo, an instance of ScmHelper is used, see line 120:

repository = getScmManager().makeScmRepository( scmHelper.getUrl() );

But the ScmHelper's URL is a reformatted URL, with user, password, and so on removed. The effect is that any attempt to run

mvn release:prepare

with an URL like scm:cvs:pserver:joe@host:/cvs:module is refused with an error message "The scm url is invalid."

I can't tell which side is wrong and am thus unable to provide a patch.