How about opening it in the audio editor, selecting the part you want to
silence and hitting delete. If you then save/export the file it should
make the change permanent. Works for me, but I have only version 3.0.

That then still keeps it all in a single (i.e., the original) soundbite
rather than breaking it up into two soundbites?

--

(Preferably reply to the newsgroup, please. If you reply by Email, I
will sincerely try to receive your message, but it will probably get
buried in spam.)