I reached a dead end, i.e., the page relating to the last line,Using other SF2 / DLS Wavetables:
Important: Soundfont (SF2) Wavetable support/selection is only available in Mixtikl 6 and Noatikl 2.5+
It is easy to use custom wavetable sounds! All you need to do is to use the left list control to select the Wavetable from the list of those shown - and seven of these are included in Mixtikl 6 / Noatikl 2.5+ [Mixtikl 5 only lists the GM DLS Wavetable]. Then use the right list control to select the Patch (all patches available in the Wavetable are listed).
To use other SF2 in the relevant versions of Mixtikl or Noatikl, simple copy or transfer them to your device.
. Is there anywhere else I can reach this information ???simple copy or transfer them to your device, is no longer available