There are two discs:
1. Buffalo HD-HBU2 ユーティリティCD version 1.20
This will work. When product number is asked, type in the number on the disc 2
It shows message to upgarde, but no web page exist anymore. But anyhow installed acronis will work in somewhat primitive way.
2. Buffalo HD-WIU2/R1 ユーティリティCD version 3.00
This won’t work.