DLO 7.5 on the same server as Backup Exec 12.5?

Currently I have one media server backup exec 2010 in my domain (windows 2003 SP2 server). And I have another server with DLO 7.5 (windows 2008 SP2 server). I have unused license of backup exec 12.5. I was wondering if it is possible to install backup exec 12.5 on the same server as DLO 7.5?

My second question is if introducing a second older version of backup exec 12.5 can cause any problem to the already main media server BE 2010 in the same domain?

I don't intend to share backup resources between the two media servers. Thanks for your thoughts