WSUS and vista = no update detected?

Hi,

I'm using WSUS to download and deploy updates from a central location.
this works fine

But I have just installed a Vista computer and the updates available for
vista are not listed in the windows update page of Vista.

Do you know if there is any issue or specific configuration to do?

if I switch my Vista setup to use the default Microsoft Update site instead
of the WSUS intranet site all the updates are listed correctly.

any idea?

thanks.

Jerome.