"Both of the new disks are listed as 'foreign'" There is your problem ... you can do nothing with them until the foreign config has been resolved.  You must CLEAR the config (import is ONLY used when an array is OFFLINE - ask first should this ever occur).  The RAID configuration is stored on the controller and on the disks ... when you insert a disk that has a previous config on it - different from the config the controller is using - it flags it as foreign until you decide what to do with it. You can clear the foreign config in CTRL-R or you can clear it in Storage, PERC, Information/Configuration, Foreign/Clear.
I just installed OpenManage Server Administrator on a server where I want to add two new disks.  When I open the window with the physical disks, the only "Available Tasks" which I get are Blink and Unblink.  This is the case for all the disks, both new and old.  What am I missing?
OpenManage 7.1 Physical Disks Available Tasks are only Blink and Unblink