Had the same issue briefly now... thought it was strange as i have the same setup on my laptop and that worked fine.

In summary:

You can have both versions of Integration services installed on a machine...

To see the integration services catalog on the sql2012 instance, you need to have the database running as well as integration services. Then you must use the sql2012 client to connect to the database engine and voila you will see it.

If you use an older version of the client, my experience is that i do not see the integration services client.