The case may be that you have those ra files already imported into Lightroom catalogue. If that is the case, and a file or a folder is already imported into Lightroom you need to trigger the synchronization of metadata manually - "read metadata" in Lightroom; that will cause Lightroom to read the new .xmp file.
One of the ways to do it is to select the files in the Lightroom Grid view (to select all files in the Grid view, you can use Ctrl-A), right-click on one of the selected files; and in the drop-down that appears choose Metadata -> Read Metadata from Files. You can do it with a single file too by right-clicking on it; you will see 'Read Metadata from File', singular.
Dear Sir:
The case may be that you have those ra files already imported into Lightroom catalogue. If that is the case, and a file or a folder is already imported into Lightroom you need to trigger the synchronization of metadata manually - "read metadata" in Lightroom; that will cause Lightroom to read the new .xmp file.
One of the ways to do it is to select the files in the Lightroom Grid view (to select all files in the Grid view, you can use Ctrl-A), right-click on one of the selected files; and in the drop-down that appears choose Metadata -> Read Metadata from Files. You can do it with a single file too by right-clicking on it; you will see 'Read Metadata from File', singular.