Please please try and use that internal...this is how bad it is:
1) Use a PerRequest shared Scope as per the documentation
2) Something happens, maybe the app pool resets, or some multithreaded event occurs (I'm not sure what, Jan was able to reproduce it though)
3) The site instantly starts throwing exceptions, not even a second of Loading...
4) Rebooting the app pool doesn't fix it, the only way to rectify the situation is to reset the IIS Service which of course resets ALL of the sites.
The designer in the official release is totally incapable of mapping tables with multiple PKs...or at least out complex schema.
Both of these are fixed in the internal release though.