XP - Vista Dual boot

I have a machine with multiple HDD's that has had Xp installed for a while. I decided to try out Vista64bit so attempted to install on a blank SATA hdd. This failed to work as the Vista installer could not/would not recognise the HDD as a bootable device. So i removed all the other HDD's and ran a fresh install and it installed fine. I then edited the boot.ini to offer OS boot options which now fails to recognise a boot sector on the Vista install. If I go through the BIOS and select the boot HDD each OS starts up without error, however this is a faff.......

Any ideas how I can get the OS choice to work correctly?