NFS Woes!

Sorry! It's me again :-( .

I am now running SlugosBE with the rootfs NFS-mounted from another machine.
That is mostly working fine. But there  are two problems.

1. It seems that NFS will not let you export files that have been NFS-imported from
elsewhere (well, exportfs will let you do it, but remote clients will decline to  mount
it with 'Permission Denied'. This is not an unreasonable restriction, but note that you
cannot even mount tmpfs files such as those in /tmp, because /tmp is _really_
/var/volatile/tmp, and it needs to go to the remotely mounted rootfs to disentangle
the /var/volatile bit.

But there seems to be a workaround. It you create a top-level tmpfs file system
(e.g. /mounts), then it seems it can be legitimately exported (so I in fact mounted my
USB stick in there, and the contents of the stick are visible from the slug). Next
problem was to make them visible to my main machine, and that brings me to the
next problem:

2. The client seems willing to mount that /mounts, and it persuades the slug to
respond to the MOUNT3 packet, but then it fails to make an NFS connection. It
seems that the nfsd on the nslug had failed to tell the portmapper what port number
it would like to be contacted upon. If I look in /var/run/portmap_mapping, I can see
100000 2 6 111 1
100000 2 17 111 1
100005 1 17 1022 1
100005 1 6 601 1
100005 2 17 1022 1
100005 2 6 601 1
100005 3 17 1022 1
100005 3 6 601 1
100024 1 17 605 1
100024 1 6 608 1
but 100003 (for NFS) is conspicuously absent from that list, and without it the client
refuses to complete the mount (the 100005 is the MOUNT itself, and is fine).

AFFAICT, nfsd is properly installed; modprobe is happy with it, and /proc/modules
contains:
nls_utf8 1120 1 - Live 0xbf0ad000
nls_cp437 4608 1 - Live 0xbf0aa000
vfat 10496 1 - Live 0xbf0a6000
fat 42908 1 vfat, Live 0xbf09a000
nls_base 5024 4 nls_utf8,nls_cp437,vfat,fat, Live 0xbf097000
nfsd 186588 0 - Live 0xbf068000
exportfs 4352 1 nfsd, Live 0xbf065000
ohci_hcd 16804 0 - Live 0xbf05f000
ehci_hcd 30252 0 - Live 0xbf056000
nfs 108576 1 - Live 0xbf03a000
lockd 51384 2 nfsd,nfs, Live 0xbf02c000
sunrpc 131920 4 nfsd,nfs,lockd, Live 0xbf00a000
ixp4xx_mac 14612 0 - Live 0xbf005000
ixp4xx_qmgr 5388 5 ixp4xx_mac, Live 0xbf002000
mii 3424 1 ixp4xx_mac, Live 0xbf000000

So what am I missing?

And a final niggle:

3. I installed module-init-tools-doc, but the list of files it brought over was empty.