I use 3.05. Go to --> Tools --> Wave Pad Options --> Keys --> Add (pick any key / key combination) and follow through using common sense.
In this way I use the x key for "stop", the z key for play, the ctrl - x for cut, the a for amplify (selection) (it will ask for a percentage first) and the s key for silence (selection).
Also, after recording my speech from the book i am reading (study) i use the g key for a lot of sequential actions. It filters noise, trims silences, inserts a sound bite at the end, adds 3 seconds of nothing at the end...
You have to be a registered user though. So pay first! 
(By the way can some one working at WavePad's company try to contact me, I have some stuff I would like to suggest for the next version).