Anyone else here running gentoo? I can't figure out what I need to enable in the kernel to get my player working properly.
You have three options (all of them really do the same behind the scenes): enable CONFIG_SCSI_MULTI_LUN in the kernel, set the max_luns option of the scsi_mod module to at least 2 when loading it, or set /sys/module/scsi_mod/parameters/max_luns to at least 2.
When you've done that, please go and complain loudly to whoever decided that CONFIG_SCSI_MULTI_LUN should be off in a gentoo kernel. No other distribution has this problem.