Managing a innexistant Windows service result in error "Could not evaluate"

After writing a class to manage services for all machines, I found out that Puppet errors out when the service is missing with an error maybe related to the use of French Windows workstation:
Error: /Stage[main]/Win7service/Service[jhi_service]: Could not evaluate: invalid byte sequence in UTF-8

Since there's no onlyif, I can not check if the service executable is present beforehand.