Windows 2003 & Wireless connection?

Hi,

I'm trying to connect my Windows 2003 machine to a wireless router using a
network key I generated on my router admin utility.

When I try to configure this key in the Wireless Properties, I get an error
stating..

"The network key you entered is incorrect. The key can either be a
hexadecimal (10 or 26 digits) or ascii text (5 or 13 characters)"

BUT, when I configure this setting on a Windows XP machine I have the option
to specify the key format (hex or ascii) and the key length without a problem
and everything works OK.

These dropdowns are not available in Windows 2003. What am I missing???

Thanks, Dave.