Peter is correct, The Seed list instructions and a .txt example is actually detailed in the help menu of Balance. The Seed list option is only for "Physical" servers and not VM's. And lastly, even if you already added a proxy server to Balance you will still need to specify the "proxy" name in the seed list for the discovery of "Windows" platforms.
The seed list will error if there is something missing with an error of "Line 5 missing blah".
best regards,
Don Bourque