My HP SJ5P scsi connected scanner, which is ages older than yours, is
running fine under VISTA since I did what I did for W2K and XP --
install the HP Deskscan 2.9 software that uses the TWAIN connection.
You can download Deskscan 2.9 from the HP website if you search for
that name. Install it as Run as Administrator and do the Scanner Test
at the end -- my balloon floated up nicely.