Since I was struggling for the proper syntax of the commands mentioned above, I googled a lot trying to get the powercli structure of the command as opposed to the all bunch of ssh you can find for esxcli and I found this :http://blogs.vmware.com/vsphere/2012/01/automating-datastore-storage-device-detachment-in-vsphere-5.html
I started playing with it and my guess is it should help and simplify a lot the all mount/unmount process 
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Sorry I couldn't figure out the way to use powercli esxcli
Thanks