I am not a product expert but I have moved your post to the ePO area. Hopefully someone can help you soon!
I've translated your post to read in English:
I have a client asks me for help installing ePO4.5, knowing that he is not a machine dedicated to ePO server.
He asked me is it can coexist in the same machine ePO server containing a backup solution. for information, it has a domain controller, a gateway ISA Server Database and a storage server.
The backup software used is not chosen, it can be SCDPM2010 Symantec Backup Exec or Microsoft).
Your help is valuable.