Many thanks for the detailed explanation. I didn't find the soundtrack split button...so I had to clear my glasses. 
It works right as you say. One little function I miss is to clone a sound clip in the sequencer, for example background music from one film clip to use it with another because there is only wind sound or such things. Copy - Paste in sequencer would solve this problem.
But I have found a simple workaround for this. I place the positon marker in sequencer, start externally Audacity, press "Record" and then sequencer play in Videopad. After recording some trimming in Audacity and import this sound file in Audacity. This I can put in sequencer as often I need it.