How can I convince my manager to contribute back to the open source community? [on hold]

I'm currently working within a large corporation that has a department specifically for open source development. The idea being, someone comes to us with a project, and we develop solutions based on what's out there in the open source community.

I recently had my knuckles rapped by my line manager for doing a series of tutorials. Two of the projects in question where Liferay and Teiid in this case. I created some simple github tutorials to share with people and started to do some youtube videos on Teiid. My line manager took me into the office and told me to delete the github code and to remove the videos otherwise I'd be subject to disciplinary action.

All of this was done on my own time and never on the companies time as we were too busy capitalising on open source projects and never giving anything back. The code was checked into my own public Github account. In my videos and in my code there was no reference to my employer or any of it's projects. My line manager had even gone through my code line by line and couldn't find anything that tied the work back to the company.

I did this with the best intentions. We are supposed to be open source developers, yet the company has yet to contribute a single thing back in terms of code or support to the community. I thought it would be nice to do some tutorials for my own personal development and give something back to the community. So, is there a genuine problem with doing the above? How would you go about convincing management that this is a good idea (or if you don't agree, why is it a bad idea).

Given the above situation, how would you convince management to give back to a community in which it relies on so heavily upon? What guidelines other than the steps I've already taken would you encourage other developers to follow to ensure they are confident they have the ability to contribute back to the open source community even in their own time?