Adding W7 drive to XP machine (with a twist)

My company is running several XP machines. All of these machines will need to have a hard drive added to them that will be imaged with our corporate Win7 image.

The big question: How can I get the Win7 bootloader to recognize the XP install?

Hard Part: We don't want to have to use a 3rd party app such as EasyBCD. We would like to create a batch file that utilizes the capabilities of bcdedit.exe to modify the bootloader so we can repeat the process multiple times with out installing the 3rd party app. (plus, the boss doesn't want us using the 3rd party app)

With separate HD's the cleanest dual boot is via the BIOS, which keeps the HD's independent to come and go as you please. A Windows-managed Dual Boot interlocks the HD's so they are harder to remove, and is more volatile.

Set the preferred HD to boot first (after DVD drive) in BIOS Setup under Boot Order. Then to boot the other OS HD, tap the key given on first boot screen for one-time BIOS Boot Menu, which on Asus mobos is normally F8. Then select the desired HD to boot.

Thanks for the reply gregrocker. If I can't find a way to do this in the fashion I wish, I may just have to use the BIOS option. But from what I remember, our computers have BIOS that do not allow changes of the drive boot order. We would have to swap (or unplug) SATA cables on the drives to determine boot order.

The hard drives will most likely be a permanent install on all the machines so easy swapability is not an issue.

We were trying to get away from using the BIOS to swap drives for simplicity reasons. The IT team (two of us) will be handling all cases that require booting back into XP. So it would be easy for us if we could just modify the bootloader and then tell users to select the XP install from the bootloader menu. Does anyone know if it's possible to modify the bootoader to add the XP install with a batch file?

I'll try to talk to the boss again about running EasyBCD on each install. It might be worth the hassle in the long run.

We decided to just install Win7 onto a second hard drive within one of the XP machines. Then we will configure Win7 and create an image from it. I can't see any problems with this method so I'll give it a shot.