Overriding PromptService in newer XULRunner

Hi,
In my embedding c++ application, We override the default PromptService
to provide custom dialogs for alert, prompt, etc by

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        nsCOMPtr<nsIFactory> promptFactory;
	rv = NS_NewPromptServiceFactory(getter_AddRefs(promptFactory));
	if (NS_SUCCEEDED(rv)) {

		nsCOMPtr<nsIComponentRegistrar> compReg;
		rv = NS_GetComponentRegistrar(getter_AddRefs(compReg));
		NS_FAILED(rv, rv);

		rv = compReg->RegisterFactory(kPromptServiceCID,
			"MMPrompt Service",
			"@mozilla.org/embedcomp/prompt-service;1",
			//"@mozilla.org/prompter;1",
			promptFactory);

		NS_FAILED(rv, rv);
	}
---------------------------------------------------------------------------------------------
When using XULRunner 1.9.* versions, this works perfectly
But, this doesn't work on newer XULRunner versions (>= 4.0)

I have googled on this, but I couldn't fix it

Any help/suggestions?

Thanks,
Alvin