AFP server doesn't cross file system boundaries

On my SL server, I have a volume mounted at a custom location (instead of in /Volumes) and I'm trying share a folder to the root of this mount location over AFP. In other words, something like this:

/foo/share (share point in server manager)

/foo/share/bar/mountpoint (mount point, as defined /etc/fstab)

AFP clients can NOT see the mount point via the file share.

But Windows/Samba/SMB clients can see the mount point.

Is there a way to configure the AFP server so that AFP clients can see the mount point? i.e. cross the file system boundary

I scoured the AppleFileServer plist in /Library/Preferences and couldn't find anything useful.

Any tips welcome. Thanks!