Connecting RISC OS to Apple Airport?

Has anyone actually managed to connect a RISC OS computer to an Apple AirPort-Time-Capsule over the LAN?

I’ve tried this with LanMan98 on a ARMiniX, and although the device mounts (i.e. an icon appears on the icon bar), I can’t make access. An error box says: “Function not supported”.

When I do the same with the original Lan Manager protocol, I get an error box (Access denied) immediately, without any icon popping up.

Is it possible in the first place? (I would love to make backups on the 2Tb internal drive of that expensive device…)