The PERC 710P supports both SAS and SATA disks. I have a single RAID1 set and would like to add a RAID5 set built out of SATA disks for archival use, but I cannot confirm that a configuration like that is possible. Citations requested if possible.
Mixed SAS/SATA drives cannot be combined in a single common virtual disk or RAID set, but you can create separate VDs with various types (RAID1 on SAS, and a separate RAID5 on SATA).
Source: Documentation (below), and personal experience in Dell Storage Support.
Page 9: "Mixing SAS and SATA drives within a virtual disk is not supported. Also, mixing hard drives and SSDs within a virtual disk is not supported."
I was able to accomplish something similar what it sounds like you're wanting about a week ago; Existing VD on SATA disks, new SAS drives added to a server, and the H710 allows to create a 2nd separate VD on the added drives.