Hi,
to determine if a particular update is available for distrubution via WSUS, I check the MicrosoftUpdate catalog:
http://catalog.update.microsoft.com/v7/site/Search.aspx?q=office%202010%20service%20pack
Review the search results, and examine the Product, Classification, Language, and the specific KB articles by clicking into each.
I think the one you want is:
http://support.microsoft.com/kb/2510690
Then, check your WSUS to confirm you are synchronising the matching Product, Classification and Language
Don
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