RD240 need to use larger than 2TB capacity drives

Hello!  We have an RD240 1046 that is used as an NVR for our camera system.  I've got a bunch of 2TB drives in it, but we're running out of capacity.  There are a few open drive slots, so we purchased a couple of 6TB drives, but foud out that the LSI MegaRAID controller built in does not supprt drives larger than 2TB.  Is there a way to upgrade this server so that the system will allow the use of 6TB drives?  If so, what parts do I need?

Thanks in advance for your help!