Using a fresh installation of Jbpm 6.4.0 Final ( Full installation ) and following these instructions:

https://docs.jboss.org/jbpm/v6.0/userguide/jBPMDomainSpecificProcesses.html#d0e13857

adding twitter repository is not working.

I've also tried to add this repository service: http://docs.jboss.org/jbpm/v6.4/repository/ but is not working.

I've noticed some error on eclipse workspace log, could be useful