How to install win xp pro to external hard disc

[cybunn]

I am a notebook user (OS - win xp pro) and recently bought an external hard disc connected to my notebook through USB 2 port. My notebook was able to detect the ext hrd disc as removable disc. But I am not able to install win xp pro to my external hard disc. It stop after the hard disc partition stage. I am able to partition my ext hard disc but when i want to install win xp pro to it, the setup prompt me that it was not able to assess my ext hrd disc.

I need advise to resolve the above, please help.

regards,
cybunn