|In any event, using RAdmin Viewer 3.0 beta I have never seen the "Resume" option you reffer to|
This is not an option, this is a feature which is always enabled.
Here's an extract from Radmin 2.2 help file:
Radmin has a feature used when copying files that allows updating only a part of the file which is different on both machines. This feature is called "Delta Copy" since only files difference ("delta") is copied. It allows continuing copy operation after network faults from the place where fault occurred and not from the beginning.
This feature is used automatically when any file is being copied to or from the remote machine. For each section of source and destination files, Radmin Server and Radmin Viewer calculate control sum, and this sum (several bytes) is transferred over a network and compared. If sum is equal, this means that corresponding files portions are equal, so no data for this portion is set and next portion of both files are examined. Actual file data will be transferred only for parts that are different; witch allows continuing interrupted copy operation and updating only part of files that are actually different.