We aren't only using uddeim in a cron job. 95% of the use is in the normal http mode as users are using the website. The problem with the live_site variable and the recommendation of the CB team is documented in the forum thread I posted (3 times now) - see below (#196613). If you have questions about why CB is recommending against the use of the live_site variable, perhaps that should be taken up with them.
Getting back to our issue, we still need to find a way to make the component work in a cron job. Since the _site_ variable does work in a cron job, we are wondering why this variable is not used in forming the %msglink% variable. This question was not answered as of yet:
Do you mean that the _site_ variable relies on URL guessing and for that reason it cannot be used?