Hal07,
Your solution to back up directly to a network drive is fine.
The reason to copy locally is basically for two reasons.
1) To avoid having to muck around with permissions. (but you solved this fine)
2) Speed. The backup over the network is in general significantly slower than backing up locally and then copying the results to the backup server.
If the speed is not an issue (and depending on hardware, it may not be an issue at all), you should feel free to use your method.
Ed
Graphisoft Technical Support