After some fiddling around with ALSA if now works with kernel 2.6.32 on Lenny (using 2.6.32-trunk-AMD64). However I still have to issue an "alsa force-reload" to get the second drive working. Probably an ALSA thing and not kernel related. So I think we can conclude that the issue is still in 2.6.26 but is resolved in 2.6.32 Thanks to all who replied and those involved in the package development.
