Oh, come on! Somebody!

Shouldn't be that hard to answer my question! Are there any systems engineers there than know how the thing works?

Still waiting for an answer...

So I've cracked it myself allright.

For anyone who might be also interested, here's what solves it:

1) Make sure you connect

     - [spdif out] on your POD to [spdif in] of your clock master unit (M-Audio ProjectMix I/O in my case)

     AND

     - [spdif in] on your POD to [spdif out] of your clock master

Apparently POD expects master clock signal on its [spdif in] only, even though it might be present on the [spdif out] cable too, so connecting the [spdif in] is crucial even if you're not planning to play back anything through POD's digital input.

2) Set settings in the OUTPUTS page of the POD (press the [OUTPUTS] button) to:

     - MATCH STUDIO/DIRECT for DIGITAL

     - MATCH DIG IN for RATE

     - whatever level boost you need for LEVEL

     - S/PDIF for FORMAT

3) On the INPUTS page of the POD (press the [INPUTS] button) set:

     - anything BUT VARIAX as TONE1

     - anything BUT VARIAX as TONE2

     - S/PDIF for DIGITAL

     - DISABLE GLOBAL CONTROL for VARIAX (this last one does not really matter, will work with either setting, but just in case I have turned off variax control)

Now, it's this last step (3) that I have missed originally in my vain attempts to make POD work as a sync slave.

When you think of it, it's just obvious that when you have Variax connected to the POD, the POD should rule the digital interface and be the clock master. I don't have a Variax, so I don't care. So as soon as I have delisted Variax as one of the signal sources for the tones in the INPUTS page, my POD happily sold itself to slavery to my M-Audio board.

Peace,

Dmitry.

P.S. Yes, my question has been answered, but not by the Line6 support, alas. No bad feelings guys, just update your manuals.