Remember Lightroom 5 is a Beta for testing only. It is not designed to be a production tool at this time. You are prevented from bringing catalogs wholesale in for this reason.
You can save your metadata to XMP files that Lightroom can read. Select a group of images you want to experiment with in Lightroom 5 and hit [Ctrl/Cmd][S] to save the XMP files to your disk.
You can then import this subset of your photos into LR 5 and it will read your XMP Data and add back in most of what you are missing. Some items are stored in the catalog and not in XMP and will not come over until the final version of LIghtroom allows you to update your catalog.
BTW, there is a Lightroom 5 forum to post items like this. http://forums.adobe.com/community/labs/lightroom5/