Hi Georgi,
Thanks for your response - this solves my problem!
I also noticed that there is also possible to set the default value for metafields in web.config. For example this is for the Publication_date
<add key="News.Publication_Date" valueType="DateTime" visible="True" searchable="True" sortable="True" defaultValue="#Now" />
Difference is that these valus are applied already when user enters the create news page, where with your solution it is applied on save. Would be great if you could add a shorthand for the user name that could be used here as well. Or maybe some simple expression minilanguage to combine several fields like you did with the FirstName and LastName from user profile.
Thanks!
-Szymon