First of all you need to connect the two 2882's per firewire, ensure that one is word clock master, the other slave, you may want to connect the two to each other's bnc sockets. Then create an aggregate device, consisiting of the two 2882s, in Apple's audio midi setup. Make sure that both are word synced and at the same sample frequency - you will see this in MIO console.
Once you have done that, the aggregate device should appear in Logic's audio settings panel, select it, let core audio reload, and it should allow you to access all the I/O of both devices. Check the inputs available on a logic channel strip in the mixer - there should now be something like 36 listed.
You will then need to figure out which inputs in logic correspond to which physical inputs of the two 2882s. Going from memory, analog ins 1 to 8 of the 1st 2882 will be inputs 1-8 in logic, the 8 analog ins of the second 2882 should be something inputs 17-25 or 19-27.
You may also find that an aggregate device will not allow you to work at lower latency settings as a single 2882.
kind regards
Mark
