Here are some typical answers(ranked in ascending order of corniness) I get from managers/bosses whenever I bring up the importance of having unit tests and code coverage as
Why don't you just write unit tests for your code? Do you know if there are some other developers having the same problem? Probably they will follow your example and write unit tests, too.
I don't think that the problem is the technique or the costs for an integration server. The problem is the management's attitude to unit testing. So convince them with all developers.
There are lots of hints in this thread (Jon Limjap's answer), try it!