I think that the release process should use the release plugin rather than the maven-release classes directly.
Actually, it's possible to choose the maven installation to execute the compilation in continuum, BUT the maven version used to release a project can't be changed because of the compilation/runtime dependency of continuum-release.
Also, if I configure the release plugin in pom.xml (for default values or to use a specific version of the plugin), this is ignored by continuum.
What do you think about externalize the release execution using external command line as you do to execute scheduled goals ? Is there any blocker issue so that it's not possible ?