EQUAL predicate beween Object types and Strings - Breaks in 2006

Here is a question I received on my blog:

We have hundreds of BTS2004 rules where we use the EQUAL predicate beween Object types and Strings.
Now I discovered that BTS2006 does not permit this anymore. Why is it undocumented? How do I migrate those Rules in BTS2006 ?

SINCE I don't have an email address to respond to, I am posting the answer here.

ANSWER: This is a known bug that was not caught in the regression test. The SDE (Software Design Engineer) for BRE is aware of the bug and have the fix for it. However, you need to open an issue with our BizTalk support team and have it escalated to (QFE) Quick Fix Engineering team to get the fix.