828 I with 2408 mkII .. aggregate?

[zoink]

I'm creating an aggregate device in audio setup of these 2 cards. however, the virtual aggregate device won't show in Live ableton or Logic.

I've got them both synced up fine with motu dtp. spdif for 828 and WC for 2408.

is it possible that audiowire and firewire sound interfaces can't really be aggregate? that i would actually need another 2408 instead of the 828... or the other way around a second 828? i know a friend of mine used 2 x 828 linked up just fine.. and well since 2408 is actually built to stack up.. but before i sell my 828 mk I or trade for another 2408 i need to know...