Dualboot xp64/32 with 64 installed first

Hi

I am sorting out dualboot for someone and they would like32bit and 64 bit xp dualboot

They already have xp 64 bit installed with alot of data on the partition so I need to install 32 bit after 64bit

Does this require extra steps with bootloader type stuff? as 32bit is older than 64bit?

If it does require extra steps could someone point me in the right direction (I can find answers to almost every imaginable dualboot question except this 1)

Thanks