Access WinXP Pro shares from older MS network

I have now been trying to get a box running XP Pro (not joined any domain)
to work in a peer-to-peer network with Win98 and LanMan DOS (network boot
disk).

I understand that MS now have made the peer-to-peer different than earlier,
but I can't really understand in what way. I have been running "Windows XP
Simple File Sharing" and disabled "ForceGuest" in the Reg.database.

So now I am able to share folders like "in the old days" with WinNT Pro and
assign ressources as I am used to.

But... it does not seem to work. When I use a bootdisk (which works up
against a Win2k server) to do a "net use" against the XP Pro, it does not
connect to the XP Pro, but returns an error instead. No personal firewall
installed on any PC, neither ICF is running.

If I try to connect (browse via Network Neighbourghood) to the WinXP Pro
from a Win98, it also returns an error. The XP Pro does show up in the
browse list though.

I am accessing with usernames and passwords that are created and granted on
the XP box. What more do I need to do in order to get it working as with
WinNT?

Regards, Lars.