You "should" be able to use Dell's 2008x64 driver (hard drive format - extract before use): www.dell.com/.../poweredge-1800 The fact that Dell does not list the CERC driver for 2008 R2 means one of two things:  1) the CERC is not supported in 2008 R2 by Dell, or 2) the needed driver is already included in the OS. One other thing to consider ... I don't remember if the CERC supports non-RAID or not ... if not, then you MUST configure the drive(s) in CTRL-A before attempting to install, or even with the correct drivers, no drives will be seen to install to. All that said, it is possible that a Dell driver was never used originally, and/or the 2610sa (which I could not find on Adaptec's site - sure that is the correct model number?) is similar but not similar enough to use a CERC driver.
I have a poweredge 1800 with an adaptec 2610sa sata raid controller card.  It is basically the same card as the Dell CERC 1.5/6 sata controller.   I had this working under windows 2008 R2 before.  I had to rebuild the server from scratch.  Cant find a driver/update that will run under windows 2008 R2.   I think before I loaded the driver during the windows install process.  The only drivers I can find are for Windows 2008.  They will not install to update the driver via device manager, and everything I have downloaded from Dell will not run on R2.   Any ideas to get it working again?   Thanks.
Poweredge 1800 with CERC1.5/6 Adaptec 2610sa