How was dar file created? Is it created in another WFA setup and you are trying to import it to a new machine? If yes, could you share with me, I would like test it on my setup.
Did you try searching the command? sometime our eyes can't catch it . (Designer->Commands->(Keep mouse on Name column just beside icon ^). You will see another icon ' v ' appearing. Click on that and search for your command.
Regarding installation of 'pirate pack for vmware'. What is Pirate pack of vmware? How are you trying to use it in WFA?
I got know about 'pirate pack' from my colleague. I imported all 3 (workflow_vmware_fcp_datastore, workflow_vmware_iscsi_datastore_with_vfiler_support,workflow_vmware_nfs_datastore_with_vfiler_support) dar files and I could see all commands in my WFA.