Actually that's why I release the code on Apache/MIT combo. This way, I get to keep my code open source without forcing my company to release the modified code. Also there are no patent related issues as Apache handles that beautifully. This way, both of us get to be happy. All I want is that the original piece of my code is
1) mine for ever. Attribution wise.
2) open source for ever
3) every contributor to the code is always attributed for their work.
4) my company can make proprietary (the reason why I avoid LGPL) profits and take royalty on its modified part but my original piece must remain in the wild for me or anybody to be used freely.
Thanks for the tip. I ended up consulting a friend of mine (an attorney specialising in company law and ipr) yesterday and it turns out what I'm doing is perfectly legal and foolproof. So all's well.