aacraid not detecting drives if compiled into kernel

I'm using the Redhat kernel-2.4.21-47.EL on an IBM x3550 server which has a IBM ServeRAID 8k-l controller. I recompiled kernel to include the aacraid driver in the kernel (not as a module) for use with a bootcd. CONFIG_SCSI=y
CONFIG_BLK_DEV_SD=y
CONFIG_SCSI_AACRAID=y

When the kernel loads, the aacraid driver initializes but it does not find the drive. If I force the SCSI subsystem to rescan the host adapters, the aacraid driver finds the drive.

   # echo "scsi scan-new-devices" > /dev/scsi/scsi

However, if I compile the aacraid driver as a module, when I do a 'modprobe aacraid' the driver loads and finds the drive.

Any ideas on what is wrong and how to get around this?
I really need to have the aacraid driver compiled into the kernel for various reasons to avoid using an initrd.