FireWire 800 & FireWire 400 Hubs

I have a Mac Mini (Macmini4,1) with native FireWire 800. I have been using a 6-port FireWire 400 hub (Belkin; Model No.; F5U526-APL-S) with a 9-pin to 6-pin cable to this hub from the Mac Mini. I did not have to use the external DC power supply that came with the FW 400 hub and everything worked great.

I have only one port free on the FW 400 hub and that's reason why I have recently added a FW 800 hub (Granite Digital; Model No.; 2381).

This FW 800 hub also has an external DC power supply.

Now, in using the FW 800 hub, I have used the supplied 9-pin to 9-pin cable and one other FW 800 device (LG BD-RE) connected to the hub.

This works fine with and without the external power supply.

The problem is when adding back the FW 400 hub.

System Profiler does NOT show anything when the FW 400 hub is connected to the FW 800 hub using a 9-pin to 6-pin cable and without any external power being supplied. Question: What is going on here?

As I have a number of FW devices (both 400 & 800), I would like to have the FW 400 hub back in the mix.

Any suggestions/comments are welcomed.

Thank You for your time, H & J