how to get vista update list

Who can tell me some methods about getting OS security update list.
I want to write a c++ program which can get security update display names
list in vista and I can't use WUA lib. Who knows other methods except using
WUA.

I have tried to do something, for example:
Firstly, in windows XP, I have get the list of security updates through
enumerating registry
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Cur rentVersion\Uninstall", but
in vista, I can't, there is no information of security update in the
registry.
Secondly, I have used MsiEnumProducts and MsiEnumPatches (api of Msi.lib),
but I only got the patchs of products, not OS security update.

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thanks