Hi UI1,
There is currently not a way to load cameras in the Milestone software when the Recording Server is offline.
We do have an unofficial tool of sorts that works for Corporate, Expert, Professional+, and Express+ that can import from a CSV but the Recording Server has to be online. It is all command-line based and can do a lot of other things besides importing from CSV. We have a KB article that covers the tool:
https://supportcommunity.milestonesys.com/s/article/How-to-use-the-Configuration-Import-Export-Utility
You can run the command below to get a template of what the CSV file should look like.
ConfigImportExportUtil.exe -k hardware -n -e -f hardware.csv
Most of it is self-explanatory except for the Driver Number. To determine that, you have to look up the camera on our supported hardware list. Once you find it, click on it to take you to the more detailed information and in the top section it will list the driver number (labeled as Hardware ID).
If the IP addresses of the cameras are all in a range, it will be faster to use the Address Range Scanning portion of our Add Hardware wizard.