Configure SSL on the WSUS Server
here is another excerpt for you from the install doc
Configure SSL on the WSUS Server
On the WSUS server, open Internet Information Services (IIS) Manager. Expand Web Sites, and then expand the Web site for the WSUS server. It is recommended that the WSUS Administration custom Web site be used, but the default Web site might have been chosen when installing WSUS. Perform the following steps on the WSUS Web site or on the APIRemoting30, ClientWebService, DSSAuthWebService, SelfUpdate, ServerSyncWebService, and SimpleAuthWebService virtual directory that reside under the WSUS Web site:
- Right-click the Web site or virtual directory, and then click Properties.
- Click the Directory Security tab, and then click Edit in the Secure Communications section.
- Select Require secure channel (SSL), and then click OK.
- Click OK to close the properties for the virtual root.
- Close IIS Manager.
- Run the following command from <WSUS Installation Folder>\Tools: WSUSUtil.exe configuressl <subject name in the signing certificate>.