I use ACDsee Pro for basic digital asset management (DAM), file capture, and previewing. I prefer this to Adobe Bridge - although it is a robust file manager, it is a memory hog. And, I have been trying out the Lightroom beta 4 and, currently, the trial download of version 1.0.
The ACDsee "Properties" window uses a different database (i.e. proprietary) setup than Lightroom. So, it is unlikely that the two applications have any commonalties, such as "ratings", "color tags", etc. However they both use most of the same data fields found in a files "metadata" (EXIF and IPTC).
I use the Windows Explorer file structure for naming folders and subfolders for "shoots" or projects. I use the same file/folder structure in both ACDsee and Lightroom. So, when I load images into Lighroom I am using the same folder names that Explorer and ACDsee uses. That should take care of that basic sorting and filing needs.
The need for a common "ratings" or "keyword" for searches in either application might be through the use of fields in the metadata of an image. Look for a field in the metadata file that is common, and customizable, in both applications, and use that for the ratings, etc. As an example; notice that both apps. have a "keyword" field in metadata, which is an open field for individual use. If you add special info/ratings in that field, say while in ACDsee, that data will also show up in Lightroom. When in Lightroom you should be able to sort on that metadata field.
Perhaps this is a possible workaround?