If it's built in, I've missed it. If it isn't, has someone crafted a metadata.xml file or some other method of making FB4.5 recognize the flexunit metadata so the warnings with be gone?
We have actually created the file in the project. Unfortunately during one of the merges during develpoment the lines that were added to the build.xml file to include it correctly in the swf got dropped. We will be issuing a 4.1.1 bug fix shortly which will include having autocomplete for metadata again.