Accessibility on x64 Firefox- Namoroka

Hi,
I successfully do queryservice (IAccessible) to get the ISimpleDomNode
when my OS is 32 bit and Firefox is 32 bit. But with Firefox x64 -
Namoroka. The following queryService call fails :

		IServiceProvider *pServProv = NULL;
		pCAcc->QueryInterface(IID_IServiceProvider, (void**)&pServProv);
		ISimpleDOMNode	*pNode = NULL;
		if (pServProv)
		{
			const GUID refguid = {0x0c539790, 0x12e4, 0x11cf, 0xb6, 0x61,
									0x00, 0xaa, 0x00, 0x4c, 0xd6, 0xd8};
			HRESULT hresult = pServProv->QueryService(refguid,
IID_ISimpleDOMNode,
														   (void**)&pNode);

                        // fails
                       .........
                }
I found that the ISimpleDomNode has entries only in WOW part of
registry. My application is x64 so it could be looking not in WOW part
of registry but in the main section of registry meant for x64 apps.
that could be the reason its is failing. Any alternate suggestions to
fix this? Is ISimpleDomNode interface going to have entries in x64
part of registry in future?

Thanks,
Pradeep