Render Server

Hi Everyone.
I cant seem to figure out how i can assign the rendering to only a specified server? for instance render-07?
the code works fine but it does not submit the job to the specified server only to render
man = netrender.getmanager()
man.connect #manual "localhost"
job = man.newJob() -- current scene
job.useAllServers = false
job.suspended = true
job.specific_servers = #( "render-07", "render-09" )

any help would be appreciated.