SCVMM 2012 R2 - Problems with VM storage location

Hello , 

I have a SCVMM 2012 R2 HA Installation . Under vmm i have an 8 node hyper-v 2012 r2 cluster with cluster shared volumes. My problem is with VM placement. Every time i create a Virtual machine by default VMM chooses a spesific CSV that i don't want . Also because of a provisioning engine i work a lot creating Vm's with powershell. The same happens with powershell. By default the VM's are created in a Volume i don't want. Is there a way to change this somehow ? If i go to each node properties and in placement paths in the default paths i see all my CSV but the add-remove buttons are grayed out and i cannot remove or add anything. 

Any ideas ? 

Thanks