OS Selector does not detect my two OS

[gonefishing]

I have two OS installed , Win XP Home and Vista Premium, the OS Selector only detects Windows XP Home but when I boot into it it displays Vista what am I not doing right

[MudCrab]

Were you booting XP and Vista using Vista's boot manager before installing OSS?

Were XP and Vista "hidden" from each other or could they see each other's partitions when booted?