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?