How to delete VMs from vCD via powerCli?

Hello

for test purposes, I frequently have to remove VMs from a vApp in vCloud Director. As I would like to do it 'properly', I do not want to delete the VMs by connecting to a vCenter and run remove-vm.

get-civm ... | remove-vm ... does not work. I get the following message: Cannot validate argument on parameter 'VM'. The argument is null or empty...

Any help is appreciated!

Thanks a lot

Uschi