Hi metazone:
I don't think WAVEPAD has any TIMERs built into it (but I could be wrong, and I certainly invite corrections).
In the meantime, until we hear from a WAVEPAD official, I can recommend two recorders that do what you want to do:
http://www.roemersoftware.com/
Rick Roemer makes EASY HI-Q RECORDER which really is easy to use ($30). He also makes a FREE version (it's on the same download page), but some of the features are crippled. Since I have the "paid" version, I don't know if the timer feature will work in the free version. If it doesn't, then take a look at:
http://www.mp3mymp3.com/
(Freeware) Has both start and stop timers, but it's not nearly as intuitive to use. Took me a good long while to figure it out. But -- it absolutely WILL DO what you want it to do.
Good luck.
Jerry