Looks like all entries are lost. Even when the syntax
[{INSERT WeblogPlugin days=all, maxEntries=10 }]
works with version 2.1.106-cvs but it does not with this version. After investigation in the source this is not expected to work in version 2.0.52 of the WeblogPlugin. As workaround:
[{INSERT WeblogPlugin days=9999, maxEntries=10 }]
does the job. Finally FAQWeblog gives some more insights.