I highly doubt I'm the first to notice this issue, but I have yet to see it posted on the forum and I'm not sure where to turn in bug fix requests. So here you go.
If you have a drawing and you wish to replace the referenced part the drawing is linked to, the normal way to do so is to click on the part in the Open Part dialog box, click references, and simply double click the reference to replace the part with the new one you select. In 2010 SP1.0, this is not possible. Try as you may, it will not work, nor will it give you the option to replace. Double clicking on the path will allow you to pick a new path, but double clicking on the part will not allow you to pick a new part. Extremely frustrating.