Mirroring configuration of SQL 2005 and 2008 R2 Side by Side

Hi experts,

We are in the process of application upgrade. We have SQL 2005 as a mirrored database (MyDatabase) for our application server (principal) and it has snapshot replication database on the same instance(MyDatabase_ss).

Recently we have installed SQL 2008 R2 on the same server and now we need to configure mirror setup  for our new application server. Could you please clarify the following points,

1. Do we need to open any new port in the network  for enabling mirroring since default port is already used by SQL 2005? 
2. Any other activity needs to performed when we run two independent mirroring on same server ?

regards,

jakk