R620 SAS without raid

I bought R620. This server no any SFF inside in. But r620 has 4–hard-drive systems 2.5 inch (x4) SAS/SATA backplane and BP SAS A cable connected,backplane signal cable and backplane power cable connected. There are no integrated storage controller card. I dont want to use raid properties. I want to install 3 SAS disk and work alone. I bought Dell SAS disk,500gb 7.2K 6Gbs (model 055RMX) When I Install SAS disk. R620 LCD screen show failed message that 'PDR1024 drive mismatch detected for drive 0 in bay1.Install correct drive type.' How can I do for using SAS disk without any RERC  on R620?