Bitlocker with existing dual boot system

I read a bitlocker article by msoft that states how to run bitlocker in a dual boot environment, it talks about installing Windows 7 after turning on bitlocker for Vista and then disabling it and so on.

Im in a situation where my laptop has two seperate hard drives installed, and vista was installed when I got it, I then installed windows 7 on the seperate hard drive. When ever I startup the operating system I chose to boot takes the C drive name and the other os gets the D drive.

Windows 7 is the main os I use but want to keep Vista as well. How should I enable bitlocker on both os's and drives?

Is it as easy as starting up windows 7 and enabling bitlocker on both drives. Or do I need to log into windows 7 and enable bitlocker for its partition and then log into vista and enable it for its partition? But with the second way I would think there would be problems with 2 startup keys trying to work at one time.

Update, I logged onto windows 7 and enabled bitlocker, it only gave me the option to do the its partition. Guess I can go to vista now and enable it for that.

It would appear that Vista and Seven use different versions of Bitlocker meaning that both versions will encrypt the boot partition.

I think you would need to install the operating systems on different hard drives and disconnecting one while you install the other with booting up controlled by the BIOS instead of a normal boot menu.

Dual boot with bitlocker on both

They are both on different hard drives already.