If you want you can put the static HTML content in the file archive of SiteVision and use WebDAV URL's to refer to it in the HTML portlet. This way relative links between HTML files will work properly and you will not need a separate storage for the HTML content.
This portlet implements a technique known as "web clipping". This means that the portlet will access and fetch content from a configured location, transform it using XSLT rules that you provide, and then present the result as a part of the final page. The content fetched in this way can use the CSS styles defined by SiteVision, or extend it with its own. This ensures that the end user does not see any difference between the regular SiteVision page and the content provided by the underlying application.
This also means that the end-user browser will never access any part of the application directly, which can be crucial from a security perspective, as the application does not have to be accessible from the end-users computer. This provides a way to securely provide access to a application located on an internal network.
To use this you need the Java client which can be used to invoke the Web Service and a RDF/XML document with the appropriate content. If you want to upload content to a remote server you will also need the system account login info in order to authenticate yourself to the Web Service.