hope this fix your issue The two tools use the same common VS implementation for diagrams (the DSL tools also use it). Hence a common look and feel. Both specify classes, and allow members to be edited. However beyond that they are very different, class diagrams just generate code, but entity designer also manages mapping and ORM back end.
Recommend usage of temp table or table variable in Entity Framework 4. Update Performance Entity framework
I wish did fix the issue. Okay, I have figured out an alternative way. It's not the answer to the original question, but it will work just as well. What I have done was entered all the Descriptions from my MS SQL database into the Entity Models Documentation.Summary and Documentation.Long Description. Then I looked at some code from these two posts: