Is this still valid for version 3.0? All I see in the designer is ConnectionStringKeyNamePattern, which contains ConnectionString.{$ProviderName}
That's it. You can change it of course. I quote the manual:
**ConnectionStringKeyNamePattern **The pattern for the key in the generated config file under which the connection string for a target database is stored. A macro is required for this property: {$ProviderName}. This macro is replaced with the short name in the driver.config of the active driver. This way multiple connection strings can be emitted into the generated code without name clashes.