As far as I understand the copyright law (or at least its local version), a person cannot give up the rights on his intellectual property (i.e. I my company cannot deny that was I who wrote this and that), he can only give (exclusive) rights for somebody (e.g. a company) to use it. While these exclusive rights might be most probably contractually bound to ANY intellectual work of a person, I doubt it will pass general "boni mores" requirements...

IANAL, of course.

Jan Waclawek


PS. You said your employees don't '51 profesionally, so you won't fire them if they would publish '51-related HW/SW here (unrelated to their job, of course), would you?