Here we go:

daniel@Lizzie:~$ sudo dmraid -ay -ddd -vvv
WARN: locking /var/lock/dmraid/.lock      
NOTICE: /dev/sdc: asr     discovering     
NOTICE: /dev/sdc: ddf1    discovering     
NOTICE: /dev/sdc: hpt37x  discovering     
NOTICE: /dev/sdc: hpt45x  discovering     
NOTICE: /dev/sdc: isw     discovering     
NOTICE: /dev/sdc: isw metadata discovered 
NOTICE: /dev/sdc: jmicron discovering     
NOTICE: /dev/sdc: lsi     discovering     
NOTICE: /dev/sdc: nvidia  discovering     
NOTICE: /dev/sdc: pdc     discovering     
NOTICE: /dev/sdc: sil     discovering     
NOTICE: /dev/sdc: via     discovering     
NOTICE: /dev/sdb: asr     discovering     
NOTICE: /dev/sdb: ddf1    discovering     
NOTICE: /dev/sdb: hpt37x  discovering     
NOTICE: /dev/sdb: hpt45x  discovering     
NOTICE: /dev/sdb: isw     discovering     
NOTICE: /dev/sdb: isw metadata discovered
NOTICE: /dev/sdb: jmicron discovering
NOTICE: /dev/sdb: lsi     discovering
NOTICE: /dev/sdb: nvidia  discovering
NOTICE: /dev/sdb: pdc     discovering
NOTICE: /dev/sdb: sil     discovering
NOTICE: /dev/sdb: via     discovering
NOTICE: /dev/sda: asr     discovering
NOTICE: /dev/sda: ddf1    discovering
NOTICE: /dev/sda: hpt37x  discovering
NOTICE: /dev/sda: hpt45x  discovering
NOTICE: /dev/sda: isw     discovering
NOTICE: /dev/sda: jmicron discovering
NOTICE: /dev/sda: lsi     discovering
NOTICE: /dev/sda: nvidia  discovering
NOTICE: /dev/sda: pdc     discovering
NOTICE: /dev/sda: sil     discovering
NOTICE: /dev/sda: via     discovering
DEBUG: _find_set: searching isw_bhcifgjhfa
DEBUG: _find_set: not found isw_bhcifgjhfa
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume0
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume0
DEBUG: _find_set: not found isw_bhcifgjhfa_Volume0
DEBUG: _find_set: not found isw_bhcifgjhfa_Volume0
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume1
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume1
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume1
DEBUG: _find_set: not found isw_bhcifgjhfa_Volume1
DEBUG: _find_set: not found isw_bhcifgjhfa_Volume1
DEBUG: _find_set: not found isw_bhcifgjhfa_Volume1
NOTICE: added /dev/sdc to RAID set "isw_bhcifgjhfa"
DEBUG: _find_set: searching isw_bhcifgjhfa
DEBUG: _find_set: found isw_bhcifgjhfa
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume0
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume0
DEBUG: _find_set: found isw_bhcifgjhfa_Volume0
DEBUG: _find_set: found isw_bhcifgjhfa_Volume0
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume1
DEBUG: _find_set: searching isw_bhcifgjhfa_Volume1
DEBUG: _find_set: found isw_bhcifgjhfa_Volume1
DEBUG: _find_set: found isw_bhcifgjhfa_Volume1
NOTICE: added /dev/sdb to RAID set "isw_bhcifgjhfa"
DEBUG: checking isw device "/dev/sdb"
DEBUG: checking isw device "/dev/sdc"
DEBUG: set status of set "isw_bhcifgjhfa_Volume0" to 16
DEBUG: checking isw device "/dev/sdb"
DEBUG: checking isw device "/dev/sdc"
DEBUG: set status of set "isw_bhcifgjhfa_Volume1" to 16
RAID set "isw_bhcifgjhfa_Volume0" was activated
RAID set "isw_bhcifgjhfa_Volume1" was not activated
INFO: Activating GROUP raid set "isw_bhcifgjhfa"
NOTICE: discovering partitions on "isw_bhcifgjhfa_Volume0"
NOTICE: /dev/mapper/isw_bhcifgjhfa_Volume0: dos     discovering
WARN: unlocking /var/lock/dmraid/.lock
DEBUG: freeing devices of RAID set "isw_bhcifgjhfa_Volume0"
DEBUG: freeing device "isw_bhcifgjhfa_Volume0", path "/dev/sdb"
DEBUG: freeing device "isw_bhcifgjhfa_Volume0", path "/dev/sdc"
DEBUG: freeing devices of RAID set "isw_bhcifgjhfa_Volume1"
DEBUG: freeing device "isw_bhcifgjhfa_Volume1", path "/dev/sdb"
DEBUG: freeing device "isw_bhcifgjhfa_Volume1", path "/dev/sdc"
DEBUG: freeing devices of RAID set "isw_bhcifgjhfa"
DEBUG: freeing device "isw_bhcifgjhfa", path "/dev/sdb"
DEBUG: freeing device "isw_bhcifgjhfa", path "/dev/sdc"

As you can see, it always activate Volume0 (first RAID0) but not the second Volume1 (also RAID0)