Simple Workflow question in Sharepoint 2007

I'm new to workflows, so please excuse the novice question.

I set up a workflow on a document library configured to send an email when a new item is created. When I create a new document in this library, the email gets sent as expected. However, when I create a folder in this library, the workflow doesn't run. If I look at Workflow Status for the new folder, I don't see the workflow attached.

Is there anything special I need to do to configure this Workflow to kick-off when a folder i开发者_如何学Cs created and not just items? If this is something that must be done with code-behind, I can go that route, but it doesn't seem like something that would require code.

Thanks in advance

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Check this post : http://www.codeproject.com/KB/sharepoint/MOSS_FolderContentTypeWF.aspx