I am running flex-pmd as part of the build, not of the reporting:
Unfortunately the Jenkins PMD plugin does not trigger then because it seems to trigger only on the "pmd" and "site" goals, but not on "report" or "check" which are the two supported by the flex-pmd plugin. I would prefer not having to run an extra "site" step for the output to be picked up. Would it be possible to accept the "report" and "check" goals?
I assume that fixes it, but I didn't test it. However, I didn't find any place where the plugin actually looks out for the name of Mojo.