How to create a Win32::API::Struct struct if the struct has union in it?

Hi,

I'm wondering about how to create a SYSTEM_INFO structure from Perl:

http://msdn.microsoft.com/en-us/library/windows/desktop/ms724958(v=vs.85).aspx

to pass this to GetNativeSystemInfo(). Win32::API::Struct->typedef()
seems to support
simple structs only. Is there a way to create such a nested struct?
Otherwise, is there any
other way apart from XS?

Thanks,
Burak