Sharepoint 2010 - Office 2010 Integration - Problem when start workflow

Question

I have a Sharepoint 2010 Document Library with a workflow. This workflow starts automatically when the user publish a major version of the document.

Everything works fine when I upload documents to the library.

When I use Office 2010 and press the check-in button inside the application (Word), the workflow doesn't start.

Does anybody knows how to fix this?

Thanks.