I never knew who wrote ping either, I'm sad to say. My condonlences to his family...
As for the past tense of 'ping':
I saw a linguistics lecture at MIT or Harvard on CSPAN last year sometime. Anyway, the relevant info was that when a word is taken and applied to a new context, the other tenses of the word tend to be those that are "regular".
For example, "The batter flied out in the 3rd inning" not "The batter flew out in the 3rd inning". Even though the past tense of fly is flew, since it is a new meaning, the past tense is flied. The lector said it much better, but he had all sorts of diagrams. Watch for it sometime.
Anyway, the short of it is, since ping is a new context (i.e. its not the sound a metal object makes when struck), the past tense is probably pinged. However, as always in language, it is what it is. If you and all your friends say pung, then by definition the past tense is pung! Have fun with that!