No. At this time, the BeOS supports only the built-in SCSI interfaces on both Power Macintosh and BeBox hardware.
Fortunately for customers with these systems there is a work around. The BeOS will work with SCSI devices which are connected to the SCSI cable from the main logic board (rather than the cable which connects to the Adaptec card). You need not remove the Adaptec card as the BeOS will only recognize SCSI devices connected to the logic board SCSI bus, and will ignore all devices connected to the Adaptec card.