I also setup successfully with DS3615xs 5.2-5967.1 and even DSM 6.0.1 (6.0_7393) which downloaded from synology but it is impossible to create volume for HDD.
System is:
HP Elite 8000 CMT chipset Q43/45
Core 2 duo E8400
2GB RAM
I have tried setup in Virtual Box and get same result. Can not create volume.
So I have to use 5.2-5644.5. All things are OK.