Solutions and Projects were one of the really cool features introduced in SQL Server 2005, judging from the responses I got when I showed how it works. Personally, I use them a lot. SQL 2008 has the same feature in SQL Server Management Studio. However, SSMS 2008 breaks this feature in SQL 2005 SSMS when installed side-by-side.
See all the ugly details here:
https://connect.microsoft.com/SQLServer/feedback/ViewFeedback.aspx?FeedbackID=361706
This also affects 64-bit systems, I just happened to find it on a 32-bit box first.
I am guessing that this failure is inherited from SSMS's Visual Studio ancester, which may make it difficult for the SQL team to fix.. No matter how hard I try, I cannot come up with a good reason that it should work this way. I have thought of several bad reasons, but I will hold off on the rock throwing.
UPDATE!! SQL 2008 CU1 fixes this, at least for 64-bit systems.
Fast on the heels of SQL 2008 is the Feature Pack for SQL 2008. Cool goodies include stand-alone installers for SQLCMD and the SQL Native Client, SQL 2008 Server Management Objects, SQL 2008 pre-defined Policies, and lots more.
You can find it here.
http://www.microsoft.com/downloads/details.aspx?FamilyId=C6C3E9EF-BA29-4A43-8D69-A2BED18FE73C