I Googled some aspects of the problem and found an answer. Bee Jay on the Logic Pro Apple Discussion list suggested that I trash my audio units cache files and force Logic to rescan my audio units. When I did this, LE8 recognized the Kontact2 Player and now I can create GPO and JABB instruments in LE8.
In detail, if the Kontakt2 Player shows up in the list given by the LE8 (or LP8) audio units manager, quit Logic and throw the following files into the trash:
When Logic restarts, it will rebuild the audio units cache and the Kontakt2 Player should show up.
BTW, you probably should update to 2.2.4 before doing all of this, since that is the configuration I am using. If you are using a earlier version of the Kontakt2 Player, this tactic may not work