VS2012 DBML Changing Connection String - linq

Question

I have a solution which contains multiple projects, such as a class library, websites, services, etc.
Projects such as the class library and service have a dbml connection to the same database. This means that the projects have connection strings such as:
MySolution.ClassLibrary.DatabaseA
MySolution.ClassLibrary.DatabaseB
MySolution.ClassLibrary.DatabaseC
MySolution.Service.DatabaseA
MySolution.Service.DatabaseD
This is a bit messy as I'm duplicating the connection strings. For integration purposes, I've also added another class library of shared components - which also has access to the same databases (Different tables). So I now have 3 instances of the same connection string in some places!
As mentioned, this is not only messy, but also leaves it open to bugs because if a connection string is missing from a website or service it will end up attempting to point at our development database (because it is defaulting to the setting from the class library).
What I would really like is simply to have a non or generically namespaced version of the connection string and just share it everywhere, e.g.
MySolution.ConnectionStrings.DatabaseA
MySolution.ConnectionStrings.DatabaseB
MySolution.ConnectionStrings.DatabaseC
MySolution.ConnectionStrings.DatabaseD
Then I would point each dbml at these connection strings and job done!
The problem is that VS2012 is so buggy when changing connection strings in the (right click > properties of the) dbml. It confuses itself between app or web.configs and Settings.settings - often when selecting DatabaseConnectingStringA, it will create a new one called DatabaseConnectionStringA1, which is very frustrating! It will also always add it's own namespace to connection strings when you add it through the project settings - which is required for the dbml.
Has anyone got a trick or method to get VS to do this?

Answer 1

In the end I did find a solution. It's not perfect, but it has reduced my connection strings from 7 or 8 (in certain places) down to 4 which I can copy and paste in between all projects for the various debug/release/staging builds.
Basically, for each DBML I added a partial class with a constructor which specifically uses my connection string:
partial class MyDataContext
{
public MyDataContext() : base(ConfigurationManager.ConnectionStrings["Master.DatabaseA"].ConnectionString)
{
OnCreated();
}
}
Then, after loading the DBML file where I could see all of the tables, I right clicked and chose properties in the background and changed the connection to None.
This has meant that the Web or App Config will look for a connection string of just "Master.DatabaseA" without referencing the project namespaces.
I then also cleared out the old connection strings in the other projects and it all works cleanly now. The only issue is that I need to set the connection back to None each time a new table or stored procedure is added. The project will not build in this situation so it can't accidentally be missed.