How to attach a TFS collection from TFS 2010 to TFS 2013

Hi all.

In order to move a collection from TFS 2010 to TFS 2013 I'm doing the following:

1) On TFS 2010 server, I detached the collection.

2) On SQL Enterprise, I took a BK of the Database.

3) I copied .bak file to the new SQL Server.

4) I restored the Database.

5) On TFS 2013 Adm Console y Clicked on the Attach collection option.

6) On the 'List Available Databases' section does not appear the Database to attach. The server name and the instance name are correct.

Can someone help me, please, 

In resume, what I need to do is to move a collection from TFS 2010 to a new TFS 2013 server that are in production.

Thanks for your answer.

Regards.

Audberto.