The problem is Windows XP doesn't have a native qxl driver, but you don't need the driver installed to view the VM through your Spice client.
This is the location for the current driver.
I personally use nLite to add extra drivers into the WindowsXP iso so they are available during install.
After install the qxl driver will automatically be installed if you have integrated it into iso then you will be able to view the VM in your "Virtual Machine Manager".
During the middle of the install XP is using a basic VGA driver as a default
The problem is when you need to type in your serial number (during middle of install) you will only be able to see the display through your Spice client.
You could create an unattended installation along with the integrated driver and you could just relax until the installation was finished or you could manually install it after the installation using a Spice client to view the OS.