I need to pass the DB ConnectionString configuration from my WebApp's web.config to the NHibernate config section in a second web.config file.

In my web app my connection looks like this:
<add name="SiteSqlServer" connectionString="Data Source=.\SQLEXPRESS;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Test05.mdf;" providerName="System.Data.SqlClient" />

And i'm setting the same connection again in a second web.config file for a service:

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory>
....
.....
<property name="connection.connection_string">Data Source=.\SQLEXPRESS;Integrated Security=True;User Instance=True;AttachDBFilename=C:\MyDocuments\Projects\Test\App_Data\Test05.mdf; </property>
....
....
</session-factory>
</hibernate-configuration>

I've already tried to copy all the hibernate-configuration code in the first web.config but apparently it doesn't recognize the configuration, i'm getting an error when i do this.
The thing is that i need to have the database connection in just one web.config file not in both files, is this possible ?
Thanks in advance for any help...

Try

<property name="connection.connection_string_name">SiteSqlServer</property>

thanks for replying so fast, i've already try your advice but i'm getting the same error, maybe the fact that the second web.config is in a WCFService project has something to do with ?
In my first web config i got the connectionString, and i want to use that connection in the second webconfig without declaring again.

First web.config (Main WebApp Project)
<connectionStrings>
<add name="SiteSqlServer" connectionString="Data Source=.\SQLEXPRESS;Integrated Security=True;User Instance=True;AttachDBFilename=C:\MyDocuments\Projects\Test\App_Data\Test05.mdf;" providerName="System.Data.SqlClient" />
</connectionStrings>


Second web.config (ServiceProject)

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory>
<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
<property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property>
<property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
<property name="connection.connection_string_name">SiteSqlServer</property>
</session-factory>
</hibernate-configuration>

This one above doesn't work. but if i add the same <connectionString> tag like in the First web.config it works fine but that is what i want to avoid. The two web.config files are in separate projects.

You can try an manualle set the config file:

ISessionFactory sf = new Configuration()
.Configure("/path/to/config.cfg.xml")
.BuildSessionFactory();

or you can manually set the property in your code:

cfg.SetProperty("connection.connection_string", get_connection_string_from_other_web_config);
cfg.BuildSessionFactory();