I figured it out.
First, I unpresented the new luns. Then I ran the "multipathd -k" command and removed the entries that were "undef" and "faulty". Then I removed the sd device with "echo 1 > /sys/block/<device>/delete". I represented the new luns, ran "echo "- - -" > /sys/class/scsi_host/host0/scan" (also did with host1) and viola, my new luns were there.