Disabling the installer close button in XP

On the final dialog of my WIX installer, I have a property which sets the Finish button to be disabled.

When the Finish button is disabled, the close button at the right top of the installer automatically gets disabled in Windows 7 and Windo开发者_运维百科ws Vista.

In XP however the Finish button is disabled but the close button is enabled. Is there any way that the close button be disabled as well?

I'm not 100% certain on this, but my guess is it's a difference in behavior for the MSI version you are running. What version are you using on XP?