Yes I did. Here is the syntax:
Copy-VMGuestFile -vm $vm -source c:\myfilename -destination c:\myfilename -force -localtoguest -guestuser myuser -guestpassword mypassword
Here is what I get in response:
| Copy-VMGuestFile : 5/23/2013 1:12:09 PM | Copy-VMGuestFile | Cannot complete the operation because the file or folder c:\myfilename already exists |