If you were using a logical volume manager it would depend on which logical manager you were using. If the RAID was done in hardware it would be presented as another disk.

For example if you created a SVM volume you would have 4 disks visible in /dev/dsk from which you would create a riad5 metadevice (md), lest say it is called md100 you would then treat /dev/md/(r)dsk/md100 as a disk in the same way as a /dev/(r)dsk/cXtY device.

In veritas you would have disks, you would add these to a diskgroup and create volumes. The devices you would mount would be located in /dev/vx/dsk/<diskgroup name>/<volume name>

If the RAID5 is done in hardware you would just see an extra disk in /dev/dsk.