Major Description
It should be possible to provide preferences for the initial instantiation of portlets in PSML. These preferences customize the portlet by overriding (or adding to) the default preferences defined in the portlet.xml.
Example: If I want to have an introductory page displaying e.g. the three most important RSS feeds, then the selection of the RSS stream is related to layout, because I want a layout displaying e.g. "Company news", "Department news" and "Team issues". Binding an RSS portlet to a particular feed makes it a specific item that I want to put at a specific place. I don't want to layout three generic RSS feeds, I want to layout company, department and team news.
As I want to layout portlet instances, it is not sufficient to be able to layout portlet types. Configuring the instances within PSML would be convenient and intuitive. It would also be acceptable if I could configure the instances in some other configuration file. But only laying out three generic RSS portlets and handing the task to bind the feeds to the end user is not feasable.