You can do everything and even more, by using powershell in the first place.
A common scenario when powershell is needed during VM deployment from the library, is when the VHD files in the library is defined as dynamical expanding disks, and you want to convert the disks to Fixed Sized Disk as part of the deployment. This is an example
where powershell comes to your rescue.
I`m not sure how you intend to drop files onto the VHD, but as part of the script, you could boot the VM and copy the required files into the OS etc.
Kristian (Virtualization and some coffee: http://kristiannese.blogspot.com )
Microsoft is conducting an online survey to understand your opinion of the Technet Web site. If you choose to participate, the online survey will be presented to you when you leave the Technet Web site.