|You can absolutely do what you want, but your code needs to unprotect the worksheet first, then copy the formula, then protect the worksheet again.|
I do not have access to Excel this weekend, so I can't produce the code you need, but trust me, what you are asking for is not that complicated.
The code I offered earlier works just fine for me, with no errors, but it does not deal with the protection issue. To use it, you need to right click the sheet tab for the sheet you want to use it in, choose View Code and paste it in. Of course the sheet must not be protected.
If you look up Protect (or something similiar) in VBA Help, you might be able to figure out how to add the unprotect/protect code.
If you can wait until Monday, I'll work on it then.